Stable version 0.6.0

This release is dedicated to Factorio. If this is how much fun it is to
build factories and oppress natives, then history makes a lot of sense.

.ghci

@@ -0,0 +1 @@
+:set -idist/build/autogen -isrc

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,27 @@
+#### For bugs
+- Rule Id (if any, e.g. SC1000): 
+- My shellcheck version (`shellcheck --version` or "online"): 
+- [ ] I read the issue's wiki page, e.g. https://github.com/koalaman/shellcheck/wiki/SC2086
+- [ ] I tried on shellcheck.net and verified that this is still a problem on the latest commit
+
+#### For new checks and feature suggestions
+- [ ] shellcheck.net (i.e. the latest commit) currently gives no useful warnings about this
+- [ ] I searched through https://github.com/koalaman/shellcheck/issues and didn't find anything related
+
+
+#### Here's a snippet or screenshot that shows the problem:
+
+```sh
+
+#!/your/interpreter
+your script here
+
+```
+
+#### Here's what shellcheck currently says:
+
+
+
+#### Here's what I wanted or expected to see:
+
+

.gitignore

@@ -0,0 +1,22 @@
+# Created by https://www.gitignore.io
+
+### Haskell ###
+dist
+cabal-dev
+*.o
+*.hi
+*.chi
+*.chs.h
+.virtualenv
+.hsenv
+.cabal-sandbox/
+cabal.sandbox.config
+cabal.config
+.stack-work
+
+### Snap ###
+/snap/.snapcraft/
+/stage/
+/parts/
+/prime/
+*.snap

.prepare_deploy

@@ -0,0 +1,50 @@
+#!/bin/bash
+# This script packages up Travis compiled binaries
+set -ex
+shopt -s nullglob
+cd deploy
+
+cp ../LICENSE LICENSE.txt
+sed -e $'s/$/\r/' > README.txt << END
+This is a precompiled ShellCheck binary.
+      https://www.shellcheck.net/
+
+ShellCheck is a static analysis tool for shell scripts.
+It's licensed under the GNU General Public License v3.0.
+Information and source code is available on the website.
+
+This binary was compiled on $(date -u).
+
+
+
+      ====== Latest commits ======
+
+$(git log -n 3)
+END
+
+for file in ./*.exe
+do
+  zip "${file%.*}.zip" README.txt LICENSE.txt "$file"
+done
+
+for file in *.linux-x86_64
+do
+  base="${file%.*}"
+  cp "$file" "shellcheck"
+  tar -cJf "$base.linux.x86_64.tar.xz" --transform="s:^:$base/:" README.txt LICENSE.txt shellcheck
+  rm "shellcheck"
+done
+
+for file in *.linux-armv6hf
+do
+  base="${file%.*}"
+  cp "$file" "shellcheck"
+  tar -cJf "$base.linux.armv6hf.tar.xz" --transform="s:^:$base/:" README.txt LICENSE.txt shellcheck
+  rm "shellcheck"
+done
+
+for file in ./*
+do
+  sha512sum "$file" > "$file.sha512sum"
+done
+

.snapsquid.conf

@@ -0,0 +1,14 @@
+# In 2015, cabal-install had a http bug triggered when proxies didn't keep
+# the connection open. This version made it into Ubuntu Xenial as used by
+# Snapcraft. In June 2018, Snapcraft's proxy started triggering this bug.
+#
+#     https://bugs.launchpad.net/launchpad-buildd/+bug/1797809
+#
+# Workaround: add more proxy
+
+visible_hostname localhost
+http_port 8888
+cache_peer 10.10.10.1 parent 8222 0 no-query default
+cache_peer_domain localhost !.internal
+http_access allow all
+

.travis.yml

@@ -0,0 +1,80 @@
+sudo: required
+
+language: sh
+
+services:
+  - docker
+
+before_install:
+  - DOCKER_BASE="$DOCKER_USERNAME/shellcheck"
+  - DOCKER_BUILDS=""
+  - TAGS=""
+  - test "$TRAVIS_BRANCH" = master && TAGS="$TAGS latest" || true
+  - test -n "$TRAVIS_TAG"          && TAGS="$TAGS stable $TRAVIS_TAG" || true
+  - echo "Tags are $TAGS"
+
+script:
+  - mkdir deploy
+  # Remove all tests to reduce binary size
+  - ./striptests
+  # Linux Docker image
+  - name="$DOCKER_BASE"
+  - DOCKER_BUILDS="$DOCKER_BUILDS $name"
+  - docker build -t "$name:current" .
+  - docker run "$name:current" --version
+  - printf '%s\n' "#!/bin/sh" "echo 'hello world'" > myscript
+  - docker run -v "$PWD:/mnt" "$name:current" myscript
+  # Copy static executable from docker image
+  - id=$(docker create "$name:current")
+  - docker cp "$id:/bin/shellcheck" "shellcheck"
+  - docker rm "$id"
+  - ls -l shellcheck
+  - ./shellcheck myscript
+  - for tag in $TAGS; do cp "shellcheck" "deploy/shellcheck-$tag.linux-x86_64"; done
+  # Linux Alpine based Docker image
+  - name="$DOCKER_BASE-alpine"
+  - DOCKER_BUILDS="$DOCKER_BUILDS $name"
+  - sed -e '/DELETE-MARKER/,$d' Dockerfile > Dockerfile.alpine
+  - docker build -f Dockerfile.alpine -t "$name:current" .
+  - docker run "$name:current" sh -c 'shellcheck --version'
+  # Linux armv6hf static executable
+  - docker run -v "$PWD:/mnt" koalaman/armv6hf-builder -c 'compile-shellcheck'
+  - for tag in $TAGS; do cp "shellcheck" "deploy/shellcheck-$tag.linux-armv6hf"; done
+  - rm -f shellcheck || true
+  # Windows .exe
+  - docker run --user="$UID" -v "$PWD:/appdata" koalaman/winghc cuib
+  - for tag in $TAGS; do cp "dist/build/ShellCheck/shellcheck.exe" "deploy/shellcheck-$tag.exe"; done
+  - rm -rf dist shellcheck || true
+  # Misc packaging
+  - ./.prepare_deploy
+
+after_success:
+  - docker login -u="$DOCKER_USERNAME" -p="$DOCKER_PASSWORD"
+  - for repo in $DOCKER_BUILDS;
+    do
+      for tag in $TAGS;
+      do
+        echo "Deploying $repo:current as $repo:$tag...";
+        docker tag "$repo:current" "$repo:$tag" || exit 1;
+        docker push "$repo:$tag" || exit 1;
+      done;
+    done;
+
+after_failure:
+  - id
+  - pwd
+  - df -h
+  - find . -name '*.log' -type f -exec grep "" /dev/null {} +
+  - find . -ls
+
+deploy:
+  provider: gcs
+  skip_cleanup: true
+  access_key_id: GOOG7MDN7WEH6IIGBDCA
+  secret_access_key:
+    secure: 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
+  bucket: shellcheck
+  local-dir: deploy
+  on:
+    repo: koalaman/shellcheck
+    all_branches: true

CHANGELOG.md

@@ -0,0 +1,360 @@
+## v0.6.0 - 2018-12-02
+### Added
+- Command line option --severity/-S for filtering by minimum severity
+- Command line option --wiki-link-count/-W for showing wiki links
+- SC2152/SC2151: Warn about bad `exit` values like `1234` and `"foo"`
+- SC2236/SC2237: Suggest -n/-z instead of ! -z/-n
+- SC2238: Warn when redirecting to a known command name, e.g. ls > rm
+- SC2239: Warn if the shebang is not an absolute path, e.g. #!bin/sh
+- SC2240: Warn when passing additional arguments to dot (.) in sh/dash
+- SC1133: Better diagnostics when starting a line with |/||/&&
+
+### Changed
+- Most warnings now have useful end positions
+- SC1117 about unknown double-quoted escape sequences has been retired
+
+### Fixed
+- SC2021 no longer triggers for equivalence classes like `[=e=]`
+- SC2221/SC2222 no longer mistriggers on fall-through case branches
+- SC2081 about glob matches in `[ .. ]` now also triggers for `!=`
+- SC2086 no longer warns about spaces in `$#`
+- SC2164 no longer suggests subshells for `cd ..; cmd; cd ..`
+- `read -a` is now correctly considered an array assignment
+- SC2039 no longer warns about LINENO now that it's POSIX
+
+## v0.5.0 - 2018-05-31
+### Added
+- SC2233/SC2234/SC2235: Suggest removing or replacing (..) around tests
+- SC2232: Warn about invalid arguments to sudo
+- SC2231: Suggest quoting expansions in for loop globs
+- SC2229: Warn about 'read $var'
+- SC2227: Warn about redirections in the middle of 'find' commands
+- SC2224/SC2225/SC2226: Warn when using mv/cp/ln without a destination
+- SC2223: Quote warning specific to `: ${var=value}`
+- SC1131: Warn when using `elseif` or `elsif`
+- SC1128: Warn about blanks/comments before shebang
+- SC1127: Warn about C-style comments
+
+### Fixed
+- Annotations intended for a command's here documents now work
+- Escaped characters inside groups in =~ regexes now parse
+- Associative arrays are now respected in arithmetic contexts
+- SC1087 about `$var[@]` now correctly triggers on any index
+- Bad expansions in here documents are no longer ignored
+- FD move operations like {fd}>1- now parse correctly
+
+### Changed
+- Here docs are now terminated as per spec, rather than by presumed intent
+- SC1073: 'else if' is now parsed correctly and not like 'elif'
+- SC2163: 'export $name' can now be silenced with 'export ${name?}'
+- SC2183: Now warns when printf arg count is not a multiple of format count
+
+## v0.4.7 - 2017-12-08
+### Added
+- Statically linked binaries for Linux and Windows (see README.md)!
+- `-a` flag to also include warnings in `source`d files
+- SC2221/SC2222: Warn about overridden case branches
+- SC2220: Warn about unhandled error cases in getopt loops
+- SC2218: Warn when using functions before they're defined
+- SC2216/SC2217: Warn when piping/redirecting to mv/cp and other non-readers
+- SC2215: Warn about commands starting with leading dash
+- SC2214: Warn about superfluous getopt flags
+- SC2213: Warn about unhandled getopt flags
+- SC2212: Suggest `false` over `[ ]`
+- SC2211: Warn when using a glob as a command name
+- SC2210: Warn when redirecting to an integer, e.g. `foo 1>2`
+- SC2206/SC2207: Suggest alternatives when using word splitting in arrays
+- SC1117: Warn about double quoted, undefined backslash sequences
+- SC1113/SC1114/SC1115: Recognized more malformed shebangs
+
+### Fixed
+- `[ -v foo ]` no longer warns if `foo` is undefined
+- SC2037 is now suppressed by quotes, e.g. `PAGER="cat" man foo`
+- Ksh nested array declarations now parse correctly
+- Parameter Expansion without colons are now recognized, e.g. `${foo+bar}`
+- The `lastpipe` option is now respected with regard to subshell warnings
+- `\(` is now respected for grouping in `[`
+- Leading `\` is now ignored for commands, to allow alias suppression
+- Comments are now allowed after directives to e.g. explain 'disable'
+
+
+## v0.4.6 - 2017-03-26
+### Added
+- SC2204/SC2205: Warn about `( -z foo )` and `( foo -eq bar )`
+- SC2200/SC2201: Warn about brace expansion in [/[[
+- SC2198/SC2199: Warn about arrays in [/[[
+- SC2196/SC2197: Warn about deprected egrep/fgrep
+- SC2195: Warn about unmatchable case branches
+- SC2194: Warn about constant 'case' statements
+- SC2193: Warn about `[[ file.png == *.mp3 ]]` and other unmatchables
+- SC2188/SC2189: Warn about redirections without commands
+- SC2186: Warn about deprecated `tempfile`
+- SC1109: Warn when finding `&`/`>`/`<` unquoted
+- SC1108: Warn about missing spaces in `[ var= foo ]`
+
+### Changed
+- All files are now read as UTF-8 with lenient latin1 fallback, ignoring locale
+- Unicode quotes are no longer considered syntactic quotes
+- `ash` scripts will now be checked as `dash` with a warning
+
+### Fixed
+- `-c` no longer suggested when using `grep -o | wc`
+- Comments and whitespace are now allowed before filewide directives
+- Here doc delimters with esoteric quoting like `foo""` are now handled
+- SC2095 about `ssh` in while read loops is now suppressed when using `-n`
+- `%(%Y%M%D)T` now recognized as a single formatter in `printf` checks
+- `grep -F` now suppresses regex related suggestions
+- Command name checks now recognize busybox applet names
+
+
+## v0.4.5 - 2016-10-21
+### Added
+- A Docker build (thanks, kpankonen!)
+- SC2185: Suggest explicitly adding path for `find`
+- SC2184: Warn about unsetting globs (e.g. `unset foo[1]`)
+- SC2183: Warn about `printf` with more formatters than variables
+- SC2182: Warn about ignored arguments with `printf` 
+- SC2181: Suggest using command directly instead of `if [ $? -eq 0 ]`
+- SC1106: Warn when using `test` operators in `(( 1 -eq 2 ))`
+
+### Changed
+- Unrecognized directives now causes a warning rather than parse failure.
+
+### Fixed
+- Indices in associative arrays are now parsed correctly
+- Missing shebang warning squashed when specifying with a directive
+- Ksh multidimensional arrays are now supported
+- Variables in substring ${a:x:y} expansions now count as referenced
+- SC1102 now also handles ambiguous `$((`
+- Using `$(seq ..)` will no longer suggest quoting
+- SC2148 (missing shebang) is now suppressed when using shell directives
+- `[ a '>' b ]` is now recognized as being correctly escaped
+
+
+## v0.4.4 - 2016-05-15
+### Added
+- Haskell Stack support (thanks,  Arguggi!)
+- SC2179/SC2178: Warn when assigning/appending strings to arrays
+- SC1102: Warn about ambiguous `$(((`
+- SC1101: Warn when \\ linebreaks have trailing spaces
+
+### Changed
+- Directives directly after the shebang now apply to the entire file
+
+### Fixed
+- `{$i..10}` is now flagged similar to `{1..$i}`
+
+
+## v0.4.3 - 2016-01-13
+### Fixed
+- Build now works on GHC 7.6.3 as found on Debian Stable/Ubuntu LTS
+
+
+## v0.4.2 - 2016-01-09
+### Added
+- First class support for the `dash` shell
+- The `--color` flag similar to ls/grep's (thanks, haguenau!)
+- SC2174: Warn about unexpected behavior of `mkdir -pm` (thanks, eatnumber1!)
+- SC2172: Warn about non-portable use of signal numbers in `trap`
+- SC2171: Warn about `]]` without leading `[[`
+- SC2168: Warn about `local` outside functions
+
+### Fixed
+- Warnings about unchecked `cd` will no longer trigger with `set -e`
+- `[ a -nt/-ot/-ef b ]` no longer warns about being constant
+- Quoted test operators like `[ foo "<" bar ]` now parse
+- Escaped quotes in backticks now parse correctly
+
+
+## v0.4.1 - 2015-09-05
+### Fixed
+- Added missing files to Cabal, fixing the build
+
+
+## v0.4.0 - 2015-09-05
+### Added
+- Support for following `source`d files
+- Support for setting default flags in `SHELLCHECK_OPTS`
+- An `--external-sources` flag for following arbitrary `source`d files
+- A `source` directive to override the filename to `source`
+- SC2166: Suggest using `[ p ] && [ q ]` over `[ p -a q ]`
+- SC2165: Warn when nested `for` loops use the same variable name
+- SC2164: Warn when using `cd` without checking that it succeeds
+- SC2163: Warn about `export $var`
+- SC2162: Warn when using `read` without `-r`
+- SC2157: Warn about `[ "$var " ]` and similar never-empty string matches
+
+### Fixed
+- `cat -vnE file` and similar will no longer flag as UUOC
+- Nested trinary operators in `(( ))` now parse correctly
+- Ksh `${ ..; }` command expansions now parse
+
+
+## v0.3.8 - 2015-06-20
+### Changed
+- ShellCheck's license has changed from AGPLv3 to GPLv3.
+
+### Added
+- SC2156: Warn about injecting filenames in `find -exec sh -c "{}" \;`
+
+### Fixed
+- Variables and command substitutions in brace expansions are now parsed
+- ANSI colors are now disabled on Windows
+- Empty scripts now parse
+
+
+## v0.3.7 - 2015-04-16
+### Fixed
+- Build now works on GHC 7.10
+- Use `regex-tdfa` over `regex-compat` since the latter crashes on OS X.
+
+## v0.3.6 - 2015-03-28
+### Added
+- SC2155: Warn about masked return values in `export foo=$(exit 1)`
+- SC2154: Warn when a lowercase variable is referenced but not assigned
+- SC2152/SC2151: Warn about bad `return` values like `1234` and `"foo"`
+- SC2150: Warn about `find -exec "shell command" \;`
+
+### Fixed
+- `coproc` is now supported
+- Trinary operator now recognized in `((..))`
+
+### Removed
+- Zsh support has been removed
+
+
+## v0.3.5 - 2014-11-09
+### Added
+- SC2148: Warn when not including a shebang
+- SC2147: Warn about literal ~ in PATH
+- SC1086: Warn about `$` in for loop variables, e.g. `for $i in ..`
+- SC1084: Warn when the shebang uses `!#` instead of `#!`
+
+### Fixed
+- Empty and comment-only backtick expansions now parse
+- Variables used in PS1/PROMPT\_COMMAND/trap now count as referenced
+- ShellCheck now skips unreadable files and directories
+- `-f gcc` on empty files no longer crashes
+- Variables in $".." are now considered quoted
+- Warnings about expansions in single quotes now include backticks
+
+
+## v0.3.4 - 2014-07-08
+### Added
+- SC2146: Warn about precedence when combining `find -o` with actions
+- SC2145: Warn when concatenating arrays and strings
+
+### Fixed
+- Case statements now support `;&` and `;;&`
+- Indices in array declarations now parse correctly
+- `let` expressions now parsed as arithmetic expressions
+- Escaping is now respected in here documents
+
+### Changed
+- Completely drop Makefile in favor of Cabal (thanks rodrigosetti!)
+
+
+## v0.3.3 - 2014-05-29
+### Added
+- SC2144: Warn when using globs in `[/[[`
+- SC2143: Suggesting using `grep -q` over `[ "$(.. | grep)" ]`
+- SC2142: Warn when referencing positional parameters in aliases
+- SC2141: Warn about suspicious IFS assignments like `IFS="\n"`
+- SC2140: Warn about bad embedded quotes like `echo "var="value""`
+- SC2130: Warn when using `-eq` on strings
+- SC2139: Warn about define time expansions in alias definitions
+- SC2129: Suggest command grouping over `a >> log; b >> log; c >> log`
+- SC2128: Warn when expanding arrays without an index
+- SC2126: Suggest `grep -c` over `grep|wc`
+- SC2123: Warn about accidentally overriding `$PATH`, e.g. `PATH=/my/dir`
+- SC1083: Warn about literal `{/}` outside of quotes
+- SC1082: Warn about UTF-8 BOMs
+
+### Fixed
+- SC2051 no longer triggers for `{1,$n}`, only `{1..$n}`
+- Improved detection of single quoted `sed` variables, e.g. `sed '$s///'`
+- Stop warning about single quoted variables in `PS1` and similar
+- Support for Zsh short form loops, `=(..)`
+
+### Removed
+- SC1000 about unescaped lonely `$`, e.g. `grep "^foo$"`
+
+
+## v0.3.2 - 2014-03-22
+### Added
+- SC2121: Warn about trying to `set` variables, e.g. `set var = value`
+- SC2120/SC2119: Warn when a function uses `$1..` if none are ever passed
+- SC2117: Warn when using `su` in interactive mode, e.g. `su foo; whoami` 
+- SC2116: Detect useless use of echo, e.g. `for i in $(echo $var)`
+- SC2115/SC2114: Detect some catastrophic `rm -r "$empty/"` mistakes
+- SC1081: Warn when capitalizing keywords like `While`
+- SC1077: Warn when using acute accents instead of backticks
+
+### Fixed
+- Shells are now properly recognized in shebangs containing flags
+- Stop warning about math on decimals in ksh/zsh
+- Stop warning about decimal comparisons with `=`, e.g. `[ $version = 1.2 ]`
+- Parsing of `|&`
+- `${a[x]}` not counting as a reference of `x`
+- `(( x[0] ))` not counting as a reference of `x`
+
+
+## v0.3.1 - 2014-02-03
+### Added
+- The `-s` flag to specify shell dialect
+- SC2105/SC2104: Warn about `break/continue` outside loops
+- SC1076: Detect invalid `[/[[` arithmetic like `[ 1 + 2 = 3 ]`
+- SC1075: Suggest using `elif` over `else if`
+
+### Fixed
+- Don't warn when comma separating elements in brace expansions
+- Improved detection of single quoted `sed` variables, e.g. `sed '$d'`
+- Parsing of arithmetic for loops using `{..}` instead of `do..done`
+- Don't treat the last pipeline stage as a subshell in ksh/zsh
+
+
+## v0.3.0 - 2014-01-19
+### Added
+- A man page (thanks Dridi!)
+- GCC compatible error reporting (`shellcheck -f gcc`)
+- CheckStyle compatible XML error reporting (`shellcheck -f checkstyle`)
+- Error codes for each warning, e.g. SC1234
+- Allow disabling warnings with `# shellcheck disable=SC1234`
+- Allow disabling warnings with `--exclude`
+- SC2103: Suggest using subshells over `cd foo; bar; cd ..`
+- SC2102: Warn about duplicates in char ranges, e.g. `[10-15]`
+- SC2101: Warn about named classes not inside a char range, e.g. `[:digit:]`
+- SC2100/SC2099: Warn about bad math expressions like `i=i+5`
+- SC2098/SC2097: Warn about `foo=bar echo $foo`
+- SC2095: Warn when using `ssh`/`ffmpeg` in `while read` loops
+- Better warnings for missing here doc tokens
+
+### Fixed
+- Don't warn when single quoting variables with `ssh/perl/eval`
+- `${!var}` is now counted as a variable reference
+
+### Removed
+- Suggestions about using parameter expansion over basename
+- The `jsoncheck` binary. Use `shellcheck -f json` instead. 
+
+
+## v0.2.0 - 2013-10-27
+### Added
+- Suggest `./*` instead of `*` when passing globs to commands
+- Suggest `pgrep` over `ps | grep`
+- Warn about unicode quotes
+- Warn about assigned but unused variables
+- Inform about client side expansion when using `ssh`
+
+### Fixed
+- CLI tool now uses exit codes and stderr canonically
+- Parsing of extglobs containing empty patterns
+- Parsing of bash style `eval foo=(bar)`
+- Parsing of expansions in here documents
+- Parsing of function names containing :+-
+- Don't warn about `find|xargs` when using `-print0`
+
+
+## v0.1.0 - 2013-07-23
+### Added
+- First release

Dockerfile

@@ -0,0 +1,36 @@
+# Build-only image
+FROM ubuntu:18.04 AS build
+USER root
+WORKDIR /opt/shellCheck
+
+# Install OS deps
+RUN apt-get update && apt-get install -y ghc cabal-install
+
+# Install Haskell deps
+# (This is a separate copy/run so that source changes don't require rebuilding)
+COPY ShellCheck.cabal ./
+RUN cabal update && cabal install --dependencies-only --ghc-options="-optlo-Os -split-sections"
+
+# Copy source and build it
+COPY LICENSE Setup.hs shellcheck.hs ./
+COPY src src
+RUN cabal build Paths_ShellCheck && \
+  ghc -optl-static -optl-pthread -isrc -idist/build/autogen --make shellcheck -split-sections -optc-Wl,--gc-sections -optlo-Os && \
+  strip --strip-all shellcheck
+
+RUN mkdir -p /out/bin && \
+  cp shellcheck  /out/bin/
+
+# Resulting Alpine image
+FROM alpine:latest
+LABEL maintainer="Vidar Holen <vidar@vidarholen.net>"
+COPY --from=build /out /
+
+# DELETE-MARKER (Remove everything below to keep the alpine image)
+
+# Resulting ShellCheck image
+FROM scratch
+LABEL maintainer="Vidar Holen <vidar@vidarholen.net>"
+WORKDIR /mnt
+COPY --from=build /out /
+ENTRYPOINT ["/bin/shellcheck"]

LICENSE

@@ -0,0 +1,684 @@
+Employer mandated disclaimer:
+
+  I am providing code in the repository to you under an open source license.
+  Because this is my personal repository, the license you receive to my code is
+  from me and other individual contributors, and not my employer (Facebook).
+
+  - Vidar "koala_man" Holen
+
+----
+
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
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+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/philosophy/why-not-lgpl.html>.

README.md

@@ -0,0 +1,461 @@
+[![Build Status](https://travis-ci.org/koalaman/shellcheck.svg?branch=master)](https://travis-ci.org/koalaman/shellcheck)
+
+# ShellCheck - A shell script static analysis tool
+
+ShellCheck is a GPLv3 tool that gives warnings and suggestions for bash/sh shell scripts:
+
+![Screenshot of a terminal showing problematic shell script lines highlighted](doc/terminal.png)
+
+The goals of ShellCheck are
+
+- To point out and clarify typical beginner's syntax issues that cause a shell
+  to give cryptic error messages.
+
+- To point out and clarify typical intermediate level semantic problems that
+  cause a shell to behave strangely and counter-intuitively.
+
+- To point out subtle caveats, corner cases and pitfalls that may cause an
+  advanced user's otherwise working script to fail under future circumstances.
+
+See [the gallery of bad code](README.md#user-content-gallery-of-bad-code) for examples of what ShellCheck can help you identify!
+
+## Table of Contents
+
+- [How to use](#how-to-use)
+  - [On the web](#on-the-web)
+  - [From your terminal](#from-your-terminal)
+  - [In your editor](#in-your-editor)
+  - [In your build or test suites](#in-your-build-or-test-suites)
+- [Installing](#installing)
+- [Travis CI](#travis-ci)
+- [Compiling from source](#compiling-from-source)
+  - [Installing Cabal](#installing-cabal)
+  - [Compiling ShellCheck](#compiling-shellcheck)
+  - [Running tests](#running-tests)
+- [Gallery of bad code](#gallery-of-bad-code)
+  - [Quoting](#quoting)
+  - [Conditionals](#conditionals)
+  - [Frequently misused commands](#frequently-misused-commands)
+  - [Common beginner's mistakes](#common-beginners-mistakes)
+  - [Style](#style)
+  - [Data and typing errors](#data-and-typing-errors)
+  - [Robustness](#robustness)
+  - [Portability](#portability)
+  - [Miscellaneous](#miscellaneous)
+- [Testimonials](#testimonials)
+- [Ignoring issues](#ignoring-issues)
+- [Reporting bugs](#reporting-bugs)
+- [Contributing](#contributing)
+- [Copyright](#copyright)
+
+## How to use
+
+There are a number of ways to use ShellCheck!
+
+### On the web
+
+Paste a shell script on https://www.shellcheck.net for instant feedback.
+
+[ShellCheck.net](https://www.shellcheck.net) is always synchronized to the latest git commit, and is the easiest way to give ShellCheck a go. Tell your friends!
+
+### From your terminal
+
+Run `shellcheck yourscript` in your terminal for instant output, as seen above.
+
+### In your editor
+
+You can see ShellCheck suggestions directly in a variety of editors.
+
+* Vim, through [ALE](https://github.com/w0rp/ale), [Neomake](https://github.com/neomake/neomake), or [Syntastic](https://github.com/scrooloose/syntastic):
+
+![Screenshot of Vim showing inlined shellcheck feedback](doc/vim-syntastic.png).
+
+* Emacs, through [Flycheck](https://github.com/flycheck/flycheck) or [Flymake](https://github.com/federicotdn/flymake-shellcheck):
+
+![Screenshot of emacs showing inlined shellcheck feedback](doc/emacs-flycheck.png).
+
+* Sublime, through [SublimeLinter](https://github.com/SublimeLinter/SublimeLinter-shellcheck).
+
+* Atom, through [Linter](https://github.com/AtomLinter/linter-shellcheck).
+
+* VSCode, through [vscode-shellcheck](https://github.com/timonwong/vscode-shellcheck).
+
+* Most other editors, through [GCC error compatibility](shellcheck.1.md#user-content-formats).
+
+### In your build or test suites
+
+While ShellCheck is mostly intended for interactive use, it can easily be added to builds or test suites.
+
+ShellCheck makes canonical use of exit codes, and can output simple JSON, CheckStyle compatible XML, GCC compatible warnings as well as human readable text (with or without ANSI colors). See the [Integration](https://github.com/koalaman/shellcheck/wiki/Integration) wiki page for more documentation.
+
+## Installing
+
+The easiest way to install ShellCheck locally is through your package manager.
+
+On systems with Cabal (installs to `~/.cabal/bin`):
+
+    cabal update
+    cabal install ShellCheck
+
+On systems with Stack (installs to `~/.local/bin`):
+
+    stack update
+    stack install ShellCheck
+
+On Debian based distros:
+
+    apt-get install shellcheck
+
+On Arch Linux based distros:
+
+    pacman -S shellcheck
+
+or get the dependency free [shellcheck-static](https://aur.archlinux.org/packages/shellcheck-static/) from the AUR.
+
+On Gentoo based distros:
+
+    emerge --ask shellcheck
+
+On EPEL based distros:
+
+    yum -y install epel-release
+    yum install ShellCheck
+
+On Fedora based distros:
+
+    dnf install ShellCheck
+
+On FreeBSD:
+
+    pkg install hs-ShellCheck
+
+On OS X with homebrew:
+
+    brew install shellcheck
+
+On OpenBSD:
+
+    pkg_add shellcheck
+
+On openSUSE
+
+    zypper in ShellCheck
+
+Or use OneClickInstall - https://software.opensuse.org/package/ShellCheck
+
+On Solus:
+
+    eopkg install shellcheck
+    
+On Windows (via [scoop](http://scoop.sh)):
+
+    scoop install shellcheck
+
+From Snap Store:
+
+    snap install --channel=edge shellcheck
+
+From Docker Hub:
+
+```sh
+docker pull koalaman/shellcheck:stable  # Or :v0.4.7 for that version, or :latest for daily builds
+docker run -v "$PWD:/mnt" koalaman/shellcheck myscript
+```
+
+or use `koalaman/shellcheck-alpine` if you want a larger Alpine Linux based image to extend. It works exactly like a regular Alpine image, but has shellcheck preinstalled.
+
+Alternatively, you can download pre-compiled binaries for the latest release here:
+
+* [Linux, x86_64](https://storage.googleapis.com/shellcheck/shellcheck-stable.linux.x86_64.tar.xz) (statically linked)
+* [Linux, armv6hf](https://storage.googleapis.com/shellcheck/shellcheck-stable.linux.armv6hf.tar.xz), i.e. Raspberry Pi (statically linked)
+* [Windows, x86](https://storage.googleapis.com/shellcheck/shellcheck-stable.zip)
+
+or see the [storage bucket listing](https://shellcheck.storage.googleapis.com/index.html) for checksums, older versions and the latest daily builds.
+
+Distro packages already come with a `man` page. If you are building from source, it can be installed with:
+
+    pandoc -s -t man shellcheck.1.md -o shellcheck.1
+    sudo mv shellcheck.1 /usr/share/man/man1
+
+## Travis CI
+
+Travis CI has now integrated ShellCheck by default, so you don't need to manually install it.
+
+If you still want to do so in order to upgrade at your leisure or ensure the latest release, follow the steps to install the shellcheck binary, bellow.
+
+## Installing the shellcheck binary
+
+*Pre-requisite*: the program 'xz' needs to be installed on the system.  
+To install it on debian/ubuntu/linux mint, run `apt install xz-utils`.  
+To install it on Redhat/Fedora/CentOS, run `yum -y install xz`.  
+
+```bash
+export scversion="stable" # or "v0.4.7", or "latest"
+wget "https://storage.googleapis.com/shellcheck/shellcheck-${scversion}.linux.x86_64.tar.xz"
+tar --xz -xvf shellcheck-"${scversion}".linux.x86_64.tar.xz
+cp shellcheck-"${scversion}"/shellcheck /usr/bin/
+shellcheck --version
+```
+
+## Compiling from source
+
+This section describes how to build ShellCheck from a source directory. ShellCheck is written in Haskell and requires 2GB of RAM to compile.
+
+### Installing Cabal
+
+ShellCheck is built and packaged using Cabal. Install the package `cabal-install` from your system's package manager (with e.g. `apt-get`, `brew`, `emerge`, `yum`, or `zypper`).
+
+On MacOS (OS X), you can do a fast install of Cabal using brew, which takes a couple of minutes instead of more than 30 minutes if you try to compile it from source.
+
+    brew install cask
+    brew cask install haskell-platform
+    cabal install cabal-install
+
+On MacPorts, the package is instead called `hs-cabal-install`, while native Windows users should install the latest version of the Haskell platform from https://www.haskell.org/platform/
+
+Verify that `cabal` is installed and update its dependency list with
+
+    $ cabal update
+
+### Compiling ShellCheck
+
+`git clone` this repository, and `cd` to the ShellCheck source directory to build/install:
+
+    $ cabal install
+
+Or if you intend to run the tests:
+
+    $ cabal install --enable-tests
+
+This will compile ShellCheck and install it to your `~/.cabal/bin` directory.
+
+Add this directory to your `PATH` (for bash, add this to your `~/.bashrc`):
+
+```sh
+export PATH="$HOME/.cabal/bin:$PATH"
+```
+
+Log out and in again, and verify that your PATH is set up correctly:
+
+```sh
+$ which shellcheck
+~/.cabal/bin/shellcheck
+```
+
+On native Windows, the `PATH` should already be set up, but the system
+may use a legacy codepage. In `cmd.exe`, `powershell.exe` and Powershell ISE,
+make sure to use a TrueType font, not a Raster font, and set the active
+codepage to UTF-8 (65001) with `chcp`:
+
+    > chcp 65001
+    Active code page: 65001
+
+In Powershell ISE, you may need to additionally update the output encoding:
+
+    > [Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+
+### Running tests
+
+To run the unit test suite:
+
+    $ cabal test
+
+## Gallery of bad code
+
+So what kind of things does ShellCheck look for? Here is an incomplete list of detected issues.
+
+### Quoting
+
+ShellCheck can recognize several types of incorrect quoting:
+
+```sh
+echo $1                           # Unquoted variables
+find . -name *.ogg                # Unquoted find/grep patterns
+rm "~/my file.txt"                # Quoted tilde expansion
+v='--verbose="true"'; cmd $v      # Literal quotes in variables
+for f in "*.ogg"                  # Incorrectly quoted 'for' loops
+touch $@                          # Unquoted $@
+echo 'Don't forget to restart!'   # Singlequote closed by apostrophe
+echo 'Don\'t try this at home'    # Attempting to escape ' in ''
+echo 'Path is $PATH'              # Variables in single quotes
+trap "echo Took ${SECONDS}s" 0    # Prematurely expanded trap
+```
+
+### Conditionals
+
+ShellCheck can recognize many types of incorrect test statements.
+
+```sh
+[[ n != 0 ]]                      # Constant test expressions
+[[ -e *.mpg ]]                    # Existence checks of globs
+[[ $foo==0 ]]                     # Always true due to missing spaces
+[[ -n "$foo " ]]                  # Always true due to literals
+[[ $foo =~ "fo+" ]]               # Quoted regex in =~
+[ foo =~ re ]                     # Unsupported [ ] operators
+[ $1 -eq "shellcheck" ]           # Numerical comparison of strings
+[ $n && $m ]                      # && in [ .. ]
+[ grep -q foo file ]              # Command without $(..)
+[[ "$$file" == *.jpg ]]           # Comparisons that can't succeed
+(( 1 -lt 2 ))                     # Using test operators in ((..))
+```
+
+### Frequently misused commands
+
+ShellCheck can recognize instances where commands are used incorrectly:
+
+```sh
+grep '*foo*' file                 # Globs in regex contexts
+find . -exec foo {} && bar {} \;  # Prematurely terminated find -exec
+sudo echo 'Var=42' > /etc/profile # Redirecting sudo
+time --format=%s sleep 10         # Passing time(1) flags to time builtin
+while read h; do ssh "$h" uptime  # Commands eating while loop input
+alias archive='mv $1 /backup'     # Defining aliases with arguments
+tr -cd '[a-zA-Z0-9]'              # [] around ranges in tr
+exec foo; echo "Done!"            # Misused 'exec'
+find -name \*.bak -o -name \*~ -delete  # Implicit precedence in find
+# find . -exec foo > bar \;       # Redirections in find
+f() { whoami; }; sudo f           # External use of internal functions
+```
+
+### Common beginner's mistakes
+
+ShellCheck recognizes many common beginner's syntax errors:
+
+```sh
+var = 42                          # Spaces around = in assignments
+$foo=42                           # $ in assignments
+for $var in *; do ...             # $ in for loop variables
+var$n="Hello"                     # Wrong indirect assignment
+echo ${var$n}                     # Wrong indirect reference
+var=(1, 2, 3)                     # Comma separated arrays
+array=( [index] = value )         # Incorrect index initialization
+echo $var[14]                     # Missing {} in array references
+echo "Argument 10 is $10"         # Positional parameter misreference
+if $(myfunction); then ..; fi     # Wrapping commands in $()
+else if othercondition; then ..   # Using 'else if'
+f; f() { echo "hello world; }     # Using function before definition
+[ false ]                         # 'false' being true
+if ( -f file )                    # Using (..) instead of test
+```
+
+### Style
+
+ShellCheck can make suggestions to improve style:
+
+```sh
+[[ -z $(find /tmp | grep mpg) ]]  # Use grep -q instead
+a >> log; b >> log; c >> log      # Use a redirection block instead
+echo "The time is `date`"         # Use $() instead
+cd dir; process *; cd ..;         # Use subshells instead
+echo $[1+2]                       # Use standard $((..)) instead of old $[]
+echo $(($RANDOM % 6))             # Don't use $ on variables in $((..))
+echo "$(date)"                    # Useless use of echo
+cat file | grep foo               # Useless use of cat
+```
+
+### Data and typing errors
+
+ShellCheck can recognize issues related to data and typing:
+
+```sh
+args="$@"                         # Assigning arrays to strings
+files=(foo bar); echo "$files"    # Referencing arrays as strings
+declare -A arr=(foo bar)          # Associative arrays without index
+printf "%s\n" "Arguments: $@."    # Concatenating strings and arrays
+[[ $# > 2 ]]                      # Comparing numbers as strings
+var=World; echo "Hello " var      # Unused lowercase variables
+echo "Hello $name"                # Unassigned lowercase variables
+cmd | read bar; echo $bar         # Assignments in subshells
+cat foo | cp bar                  # Piping to commands that don't read
+printf '%s: %s\n' foo             # Mismatches in printf argument count
+```
+
+### Robustness
+
+ShellCheck can make suggestions for improving the robustness of a script:
+
+```sh
+rm -rf "$STEAMROOT/"*            # Catastrophic rm
+touch ./-l; ls *                 # Globs that could become options
+find . -exec sh -c 'a && b {}' \; # Find -exec shell injection
+printf "Hello $name"             # Variables in printf format
+for f in $(ls *.txt); do         # Iterating over ls output
+export MYVAR=$(cmd)              # Masked exit codes
+case $version in 2.*) :;; 2.6.*) # Shadowed case branches
+```
+
+### Portability
+
+ShellCheck will warn when using features not supported by the shebang. For example, if you set the shebang to `#!/bin/sh`, ShellCheck will warn about portability issues similar to `checkbashisms`:
+
+```sh
+echo {1..$n}                     # Works in ksh, but not bash/dash/sh
+echo {1..10}                     # Works in ksh and bash, but not dash/sh
+echo -n 42                       # Works in ksh, bash and dash, undefined in sh
+trap 'exit 42' sigint            # Unportable signal spec
+cmd &> file                      # Unportable redirection operator
+read foo < /dev/tcp/host/22      # Unportable intercepted files
+foo-bar() { ..; }                # Undefined/unsupported function name
+[ $UID = 0 ]                     # Variable undefined in dash/sh
+local var=value                  # local is undefined in sh
+time sleep 1 | sleep 5           # Undefined uses of 'time'
+```
+
+### Miscellaneous
+
+ShellCheck recognizes a menagerie of other issues:
+
+```sh
+PS1='\e[0;32m\$\e[0m '            # PS1 colors not in \[..\]
+PATH="$PATH:~/bin"                # Literal tilde in $PATH
+rm “file”                         # Unicode quotes
+echo "Hello world"                # Carriage return / DOS line endings
+echo hello \                      # Trailing spaces after \
+var=42 echo $var                  # Expansion of inlined environment
+#!/bin/bash -x -e                 # Common shebang errors
+echo $((n/180*100))               # Unnecessary loss of precision
+ls *[:digit:].txt                 # Bad character class globs
+sed 's/foo/bar/' file > file      # Redirecting to input
+while getopts "a" f; do case $f in "b") # Unhandled getopts flags
+```
+
+## Testimonials
+
+> At first you're like "shellcheck is awesome" but then you're like "wtf are we still using bash"
+
+Alexander Tarasikov,
+[via Twitter](https://twitter.com/astarasikov/status/568825996532707330)
+
+## Ignoring issues
+
+Issues can be ignored via environmental variable, command line, individually or globally within a file:
+
+https://github.com/koalaman/shellcheck/wiki/Ignore
+
+## Reporting bugs
+
+Please use the GitHub issue tracker for any bugs or feature suggestions:
+
+https://github.com/koalaman/shellcheck/issues
+
+## Contributing
+
+Please submit patches to code or documentation as GitHub pull requests! Check
+out the [DevGuide](https://github.com/koalaman/shellcheck/wiki/DevGuide) on the
+ShellCheck Wiki.
+
+Contributions must be licensed under the GNU GPLv3.
+The contributor retains the copyright.
+
+## Copyright
+
+ShellCheck is licensed under the GNU General Public License, v3. A copy of this license is included in the file [LICENSE](LICENSE).
+
+Copyright 2012-2018, Vidar 'koala_man' Holen and contributors.
+
+Happy ShellChecking!
+
+
+## Other Resources                                                                          
+* The wiki has [long form descriptions](https://github.com/koalaman/shellcheck/wiki/Checks) for each warning, e.g. [SC2221](https://github.com/koalaman/shellcheck/wiki/SC2221).
+* ShellCheck does not attempt to enforce any kind of formatting or indenting style, so also check out [shfmt](https://github.com/mvdan/sh)!

Setup.hs

@@ -0,0 +1,36 @@
+import Distribution.PackageDescription (
+  HookedBuildInfo,
+  emptyHookedBuildInfo )
+import Distribution.Simple (
+  Args,
+  UserHooks ( preSDist ),
+  defaultMainWithHooks,
+  simpleUserHooks )
+import Distribution.Simple.Setup ( SDistFlags )
+
+import System.Process ( system )
+
+
+main = defaultMainWithHooks myHooks
+  where
+    myHooks = simpleUserHooks { preSDist = myPreSDist }
+
+-- | This hook will be executed before e.g. @cabal sdist@. It runs
+--   pandoc to create the man page from shellcheck.1.md. If the pandoc
+--   command is not found, this will fail with an error message:
+--
+--     /bin/sh: pandoc: command not found
+--
+--   Since the man page is listed in the Extra-Source-Files section of
+--   our cabal file, a failure here should result in a failure to
+--   create the distribution tarball (that's a good thing).
+--
+myPreSDist :: Args -> SDistFlags -> IO HookedBuildInfo
+myPreSDist _ _ = do
+  putStrLn "Building the man page (shellcheck.1) with pandoc..."
+  putStrLn pandoc_cmd
+  result <- system pandoc_cmd
+  putStrLn $ "pandoc exited with " ++ show result
+  return emptyHookedBuildInfo
+  where
+    pandoc_cmd = "pandoc -s -f markdown-smart -t man shellcheck.1.md -o shellcheck.1"

ShellCheck.cabal

@@ -0,0 +1,117 @@
+Name:             ShellCheck
+Version:          0.6.0
+Synopsis:         Shell script analysis tool
+License:          GPL-3
+License-file:     LICENSE
+Category:         Static Analysis
+Author:           Vidar Holen
+Maintainer:       vidar@vidarholen.net
+Homepage:         https://www.shellcheck.net/
+Build-Type:       Custom
+Cabal-Version:    >= 1.8
+Bug-reports:      https://github.com/koalaman/shellcheck/issues
+Description:
+  The goals of ShellCheck are:
+  .
+  * To point out and clarify typical beginner's syntax issues,
+    that causes a shell to give cryptic error messages.
+  .
+  * To point out and clarify typical intermediate level semantic problems,
+    that causes a shell to behave strangely and counter-intuitively.
+  .
+  * To point out subtle caveats, corner cases and pitfalls, that may cause an
+    advanced user's otherwise working script to fail under future circumstances.
+
+Extra-Source-Files:
+    -- documentation
+    README.md
+    shellcheck.1.md
+    -- built with a cabal sdist hook
+    shellcheck.1
+    -- convenience script for stripping tests
+    striptests
+    -- tests
+    test/shellcheck.hs
+
+custom-setup
+  setup-depends:
+    base    >= 4    && <5,
+    process >= 1.0  && <1.7,
+    Cabal   >= 1.10 && <2.5
+
+source-repository head
+    type: git
+    location: git://github.com/koalaman/shellcheck.git
+
+library
+    hs-source-dirs: src
+    if impl(ghc < 8.0)
+      build-depends:
+        semigroups
+    build-depends:
+      -- GHC 7.6.3 (base 4.6.0.1) is buggy (#1131, #1119) in optimized mode.
+      -- Just disable that version entirely to fail fast.
+      aeson,
+      base > 4.6.0.1 && < 5,
+      bytestring,
+      containers >= 0.5,
+      directory,
+      mtl >= 2.2.1,
+      parsec,
+      regex-tdfa,
+      QuickCheck >= 2.7.4,
+      -- When cabal supports it, move this to setup-depends:
+      process
+    exposed-modules:
+      ShellCheck.AST
+      ShellCheck.ASTLib
+      ShellCheck.Analytics
+      ShellCheck.Analyzer
+      ShellCheck.AnalyzerLib
+      ShellCheck.Checker
+      ShellCheck.Checks.Commands
+      ShellCheck.Checks.ShellSupport
+      ShellCheck.Data
+      ShellCheck.Formatter.Format
+      ShellCheck.Formatter.CheckStyle
+      ShellCheck.Formatter.GCC
+      ShellCheck.Formatter.JSON
+      ShellCheck.Formatter.TTY
+      ShellCheck.Interface
+      ShellCheck.Parser
+      ShellCheck.Regex
+    other-modules:
+      Paths_ShellCheck
+
+executable shellcheck
+    if impl(ghc < 8.0)
+      build-depends:
+        semigroups
+    build-depends:
+      aeson,
+      base >= 4 && < 5,
+      bytestring,
+      ShellCheck,
+      containers,
+      directory,
+      mtl >= 2.2.1,
+      parsec >= 3.0,
+      QuickCheck >= 2.7.4,
+      regex-tdfa
+    main-is: shellcheck.hs
+
+test-suite test-shellcheck
+    type: exitcode-stdio-1.0
+    build-depends:
+      aeson,
+      base >= 4 && < 5,
+      bytestring,
+      ShellCheck,
+      containers,
+      directory,
+      mtl >= 2.2.1,
+      parsec,
+      QuickCheck >= 2.7.4,
+      regex-tdfa
+    main-is: test/shellcheck.hs
+

nextnumber

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# TODO: Find a less trashy way to get the next available error code
+if ! shopt -s globstar
+then
+  echo "Error: This script depends on Bash 4." >&2
+  exit 1
+fi
+
+for i in 1 2
+do
+  last=$(grep -hv "^prop" ./**/*.hs | grep -Ewo "$i[0-9]{3}" | sort -n | tail -n 1)
+  echo "Next ${i}xxx: $((last+1))"
+done

quickrun

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+# quickrun runs ShellCheck in an interpreted mode.
+# This allows testing changes without recompiling.
+
+runghc -isrc -idist/build/autogen shellcheck.hs "$@"

quicktest

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# quicktest runs the ShellCheck unit tests in an interpreted mode.
+# This allows running tests without compiling, which can be faster.
+# 'cabal test' remains the source of truth.
+
+(
+ var=$(echo 'liftM and $ sequence [
+  ShellCheck.Analytics.runTests
+  ,ShellCheck.Parser.runTests
+  ,ShellCheck.Checker.runTests
+  ,ShellCheck.Checks.Commands.runTests
+  ,ShellCheck.Checks.ShellSupport.runTests
+  ,ShellCheck.AnalyzerLib.runTests
+    ]' | tr -d '\n' | cabal repl 2>&1 | tee /dev/stderr)
+if [[ $var == *$'\nTrue'* ]]
+then
+  exit 0
+else
+  grep -C 3 -e "Fail" -e "Tracing" <<< "$var"
+  exit 1
+fi
+) 2>&1

shellcheck.1.md

@@ -0,0 +1,225 @@
+% SHELLCHECK(1) Shell script analysis tool
+
+# NAME
+
+shellcheck - Shell script analysis tool
+
+# SYNOPSIS
+
+**shellcheck** [*OPTIONS*...] *FILES*...
+
+# DESCRIPTION
+
+ShellCheck is a static analysis and linting tool for sh/bash scripts. It's
+mainly focused on handling typical beginner and intermediate level syntax
+errors and pitfalls where the shell just gives a cryptic error message or
+strange behavior, but it also reports on a few more advanced issues where
+corner cases can cause delayed failures.
+
+ShellCheck gives shell specific advice. Consider this line:
+
+    (( area = 3.14*r*r ))
+
++ For scripts starting with `#!/bin/sh` (or when using `-s sh`), ShellCheck
+will warn that `(( .. ))` is not POSIX compliant (similar to checkbashisms).
+
++ For scripts starting with `#!/bin/bash` (or using `-s bash`), ShellCheck
+will warn that decimals are not supported.
+
++ For scripts starting with `#!/bin/ksh` (or using `-s ksh`), ShellCheck will
+not warn at all, as `ksh` supports decimals in arithmetic contexts.
+
+
+# OPTIONS
+
+**-a**,\ **--check-sourced**
+
+:   Emit warnings in sourced files. Normally, `shellcheck` will only warn
+    about issues in the specified files. With this option, any issues in
+    sourced files files will also be reported.
+
+**-C**[*WHEN*],\ **--color**[=*WHEN*]
+
+:   For TTY output, enable colors *always*, *never* or *auto*. The default
+    is *auto*. **--color** without an argument is equivalent to
+    **--color=always**.
+
+**-e**\ *CODE1*[,*CODE2*...],\ **--exclude=***CODE1*[,*CODE2*...]
+
+:   Explicitly exclude the specified codes from the report. Subsequent **-e**
+    options are cumulative, but all the codes can be specified at once,
+    comma-separated as a single argument.
+
+**-f** *FORMAT*, **--format=***FORMAT*
+
+:   Specify the output format of shellcheck, which prints its results in the
+    standard output. Subsequent **-f** options are ignored, see **FORMATS**
+    below for more information.
+
+**-S**\ *SEVERITY*,\ **--severity=***severity*
+
+:   Specify minimum severity of errors to consider. Valid values are *error*,
+    *warning*, *info* and *style*.    The default is *style*.
+
+**-s**\ *shell*,\ **--shell=***shell*
+
+:   Specify Bourne shell dialect. Valid values are *sh*, *bash*, *dash* and *ksh*.
+    The default is to use the file's shebang, or *bash* if the target shell
+    can't be determined.
+
+**-V**,\ **--version**
+
+:   Print version information and exit.
+
+**-W** *NUM*,\ **--wiki-link-count=NUM**
+
+:   For TTY output, show *NUM* wiki links to more information about mentioned
+    warnings. Set to 0 to disable them entirely.
+
+**-x**,\ **--external-sources**
+
+:   Follow 'source' statements even when the file is not specified as input.
+    By default, `shellcheck` will only follow files specified on the command
+    line (plus `/dev/null`). This option allows following any file the script
+    may `source`.
+
+
+# FORMATS
+
+**tty**
+
+:   Plain text, human readable output. This is the default.
+
+**gcc**
+
+:   GCC compatible output. Useful for editors that support compiling and
+    showing syntax errors.
+
+    For example, in Vim, `:set makeprg=shellcheck\ -f\ gcc\ %` will allow
+    using `:make` to check the script, and `:cnext` to jump to the next error.
+
+        <file>:<line>:<column>: <type>: <message>
+
+**checkstyle**
+
+:   Checkstyle compatible XML output. Supported directly or through plugins
+    by many IDEs and build monitoring systems.
+
+        <?xml version='1.0' encoding='UTF-8'?>
+        <checkstyle version='4.3'>
+          <file name='file'>
+            <error
+              line='line'
+              column='column'
+              severity='severity'
+              message='message'
+              source='ShellCheck.SC####' />
+            ...
+          </file>
+          ...
+        </checkstyle>
+
+**json**
+
+:   Json is a popular serialization format that is more suitable for web
+    applications. ShellCheck's json is compact and contains only the bare
+    minimum.
+
+        [
+          {
+            "file": "filename",
+            "line": lineNumber,
+            "column": columnNumber,
+            "level": "severitylevel",
+            "code": errorCode,
+            "message": "warning message"
+          },
+          ...
+        ]
+
+# DIRECTIVES
+ShellCheck directives can be specified as comments in the shell script
+before a command or block:
+
+    # shellcheck key=value key=value
+    command-or-structure
+
+For example, to suppress SC2035 about using `./*.jpg`:
+
+    # shellcheck disable=SC2035
+    echo "Files: " *.jpg
+
+To tell ShellCheck where to look for an otherwise dynamically determined file:
+
+    # shellcheck source=./lib.sh
+    source "$(find_install_dir)/lib.sh"
+
+Here a shell brace group is used to suppress a warning on multiple lines:
+
+    # shellcheck disable=SC2016
+    {
+      echo 'Modifying $PATH'
+      echo 'PATH=foo:$PATH' >> ~/.bashrc
+    }
+
+Valid keys are:
+
+**disable**
+:   Disables a comma separated list of error codes for the following command.
+    The command can be a simple command like `echo foo`, or a compound command
+    like a function definition, subshell block or loop.
+
+**source**
+:   Overrides the filename included by a `source`/`.` statement. This can be
+    used to tell shellcheck where to look for a file whose name is determined
+    at runtime, or to skip a source by telling it to use `/dev/null`.
+
+**shell**
+:   Overrides the shell detected from the shebang.  This is useful for
+    files meant to be included (and thus lacking a shebang), or possibly
+    as a more targeted alternative to 'disable=2039'.
+
+# ENVIRONMENT VARIABLES
+The environment variable `SHELLCHECK_OPTS` can be set with default flags:
+
+    export SHELLCHECK_OPTS='--shell=bash --exclude=SC2016'
+
+Its value will be split on spaces and prepended to the command line on each
+invocation.
+
+# RETURN VALUES
+
+ShellCheck uses the follow exit codes:
+
++ 0: All files successfully scanned with no issues.
++ 1: All files successfully scanned with some issues.
++ 2: Some files could not be processed (e.g. file not found).
++ 3: ShellCheck was invoked with bad syntax (e.g. unknown flag).
++ 4: ShellCheck was invoked with bad options (e.g. unknown formatter).
+
+# LOCALE
+This version of ShellCheck is only available in English. All files are
+leniently decoded as UTF-8, with a fallback of ISO-8859-1 for invalid
+sequences. `LC_CTYPE` is respected for output, and defaults to UTF-8 for
+locales where encoding is unspecified (such as the `C` locale).
+
+Windows users seeing `commitBuffer: invalid argument (invalid character)`
+should set their terminal to use UTF-8 with `chcp 65001`.
+
+# AUTHOR
+ShellCheck is written and maintained by Vidar Holen.
+
+# REPORTING BUGS
+Bugs and issues can be reported on GitHub:
+
+https://github.com/koalaman/shellcheck/issues
+
+# COPYRIGHT
+Copyright 2012-2015, Vidar Holen.
+Licensed under the GNU General Public License version 3 or later,
+see https://gnu.org/licenses/gpl.html
+
+
+# SEE ALSO
+
+sh(1) bash(1)

shellcheck.hs

@@ -0,0 +1,420 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+import           ShellCheck.Checker
+import           ShellCheck.Data
+import           ShellCheck.Interface
+import           ShellCheck.Regex
+
+import qualified ShellCheck.Formatter.CheckStyle
+import           ShellCheck.Formatter.Format
+import qualified ShellCheck.Formatter.GCC
+import qualified ShellCheck.Formatter.JSON
+import qualified ShellCheck.Formatter.TTY
+
+import           Control.Exception
+import           Control.Monad
+import           Control.Monad.Except
+import           Data.Bits
+import           Data.Char
+import           Data.Either
+import           Data.Functor
+import           Data.IORef
+import           Data.List
+import qualified Data.Map                        as Map
+import           Data.Maybe
+import           Data.Monoid
+import           Data.Semigroup                  (Semigroup (..))
+import           Prelude                         hiding (catch)
+import           System.Console.GetOpt
+import           System.Directory
+import           System.Environment
+import           System.Exit
+import           System.IO
+
+data Flag = Flag String String
+data Status =
+    NoProblems
+    | SomeProblems
+    | SupportFailure
+    | SyntaxFailure
+    | RuntimeException
+  deriving (Ord, Eq, Show)
+
+instance Semigroup Status where
+    (<>) = max
+
+instance Monoid Status where
+    mempty = NoProblems
+    mappend = (Data.Semigroup.<>)
+
+data Options = Options {
+    checkSpec        :: CheckSpec,
+    externalSources  :: Bool,
+    formatterOptions :: FormatterOptions,
+    minSeverity      :: Severity
+}
+
+defaultOptions = Options {
+    checkSpec = emptyCheckSpec,
+    externalSources = False,
+    formatterOptions = newFormatterOptions {
+        foColorOption = ColorAuto
+    },
+    minSeverity = StyleC
+}
+
+usageHeader = "Usage: shellcheck [OPTIONS...] FILES..."
+options = [
+    Option "a" ["check-sourced"]
+        (NoArg $ Flag "sourced" "false") "Include warnings from sourced files",
+    Option "C" ["color"]
+        (OptArg (maybe (Flag "color" "always") (Flag "color")) "WHEN")
+        "Use color (auto, always, never)",
+    Option "e" ["exclude"]
+        (ReqArg (Flag "exclude") "CODE1,CODE2..") "Exclude types of warnings",
+    Option "f" ["format"]
+        (ReqArg (Flag "format") "FORMAT") $
+        "Output format (" ++ formatList ++ ")",
+    Option "s" ["shell"]
+        (ReqArg (Flag "shell") "SHELLNAME")
+        "Specify dialect (sh, bash, dash, ksh)",
+    Option "S" ["severity"]
+        (ReqArg (Flag "severity") "SEVERITY")
+        "Minimum severity of errors to consider (error, warning, info, style)",
+    Option "V" ["version"]
+        (NoArg $ Flag "version" "true") "Print version information",
+    Option "W" ["wiki-link-count"]
+        (ReqArg (Flag "wiki-link-count") "NUM")
+        "The number of wiki links to show, when applicable.",
+    Option "x" ["external-sources"]
+        (NoArg $ Flag "externals" "true") "Allow 'source' outside of FILES"
+    ]
+
+printErr = lift . hPutStrLn stderr
+
+parseArguments :: [String] -> ExceptT Status IO ([Flag], [FilePath])
+parseArguments argv =
+    case getOpt Permute options argv of
+        (opts, files, []) -> return (opts, files)
+        (_, _, errors) -> do
+            printErr $ concat errors ++ "\n" ++ usageInfo usageHeader options
+            throwError SyntaxFailure
+
+formats :: FormatterOptions -> Map.Map String (IO Formatter)
+formats options = Map.fromList [
+    ("checkstyle", ShellCheck.Formatter.CheckStyle.format),
+    ("gcc",  ShellCheck.Formatter.GCC.format),
+    ("json", ShellCheck.Formatter.JSON.format),
+    ("tty",  ShellCheck.Formatter.TTY.format options)
+    ]
+
+formatList = intercalate ", " names
+  where
+    names = Map.keys $ formats (formatterOptions defaultOptions)
+
+getOption [] _                  = Nothing
+getOption (Flag var val:_) name | name == var = return val
+getOption (_:rest) flag         = getOption rest flag
+
+getOptions options name =
+    map (\(Flag _ val) -> val) . filter (\(Flag var _) -> var == name) $ options
+
+split char str =
+    split' str []
+  where
+    split' (a:rest) element =
+        if a == char
+        then reverse element : split' rest []
+        else split' rest (a:element)
+    split' [] element = [reverse element]
+
+toStatus = fmap (either id id) . runExceptT
+
+getEnvArgs = do
+    opts <- getEnv "SHELLCHECK_OPTS" `catch` cantWaitForLookupEnv
+    return . filter (not . null) $ opts `splitOn` mkRegex " +"
+  where
+    cantWaitForLookupEnv :: IOException -> IO String
+    cantWaitForLookupEnv = const $ return ""
+
+main = do
+    params <- getArgs
+    envOpts  <- getEnvArgs
+    let args = envOpts ++ params
+    status <- toStatus $ do
+        (flags, files) <- parseArguments args
+        process flags files
+    exitWith $ statusToCode status
+
+statusToCode status =
+    case status of
+        NoProblems       -> ExitSuccess
+        SomeProblems     -> ExitFailure 1
+        SyntaxFailure    -> ExitFailure 3
+        SupportFailure   -> ExitFailure 4
+        RuntimeException -> ExitFailure 2
+
+process :: [Flag] -> [FilePath] -> ExceptT Status IO Status
+process flags files = do
+    options <- foldM (flip parseOption) defaultOptions flags
+    verifyFiles files
+    let format = fromMaybe "tty" $ getOption flags "format"
+    let formatters = formats $ formatterOptions options
+    formatter <-
+        case Map.lookup format formatters of
+            Nothing -> do
+                printErr $ "Unknown format " ++ format
+                printErr "Supported formats:"
+                mapM_ (printErr . write) $ Map.keys formatters
+                throwError SupportFailure
+              where write s = "  " ++ s
+            Just f -> ExceptT $ fmap Right f
+    sys <- lift $ ioInterface options files
+    lift $ runFormatter sys formatter options files
+
+runFormatter :: SystemInterface IO -> Formatter -> Options -> [FilePath]
+            -> IO Status
+runFormatter sys format options files = do
+    header format
+    result <- foldM f NoProblems files
+    footer format
+    return result
+  where
+    f :: Status -> FilePath -> IO Status
+    f status file = do
+        newStatus <- process file `catch` handler file
+        return $ status `mappend` newStatus
+    handler :: FilePath -> IOException -> IO Status
+    handler file e = reportFailure file (show e)
+    reportFailure file str = do
+        onFailure format file str
+        return RuntimeException
+
+    process :: FilePath -> IO Status
+    process filename = do
+        input <- siReadFile sys filename
+        either (reportFailure filename) check input
+      where
+        check contents = do
+            let checkspec = (checkSpec options) {
+                csFilename = filename,
+                csScript = contents
+            }
+            result <- checkScript sys checkspec
+            onResult format result sys
+            return $
+                if null (crComments result)
+                then NoProblems
+                else SomeProblems
+
+parseEnum name value list =
+    case filter ((== value) . fst) list of
+        [(name, value)] -> return value
+        [] -> do
+            printErr $ "Unknown value for --" ++ name ++ ". " ++
+                       "Valid options are: " ++ (intercalate ", " $ map fst list)
+            throwError SupportFailure
+
+parseColorOption value =
+    parseEnum "color" value [
+        ("auto",   ColorAuto),
+        ("always", ColorAlways),
+        ("never",  ColorNever)
+        ]
+
+parseSeverityOption value =
+    parseEnum "severity" value [
+        ("error",   ErrorC),
+        ("warning", WarningC),
+        ("info",    InfoC),
+        ("style",   StyleC)
+        ]
+
+parseOption flag options =
+    case flag of
+        Flag "shell" str ->
+            fromMaybe (die $ "Unknown shell: " ++ str) $ do
+                shell <- shellForExecutable str
+                return $ return options {
+                            checkSpec = (checkSpec options) {
+                                csShellTypeOverride = Just shell
+                            }
+                        }
+
+        Flag "exclude" str -> do
+            new <- mapM parseNum $ filter (not . null) $ split ',' str
+            let old = csExcludedWarnings . checkSpec $ options
+            return options {
+                checkSpec = (checkSpec options) {
+                    csExcludedWarnings = new ++ old
+                }
+            }
+
+        Flag "version" _ -> do
+            liftIO printVersion
+            throwError NoProblems
+
+        Flag "externals" _ ->
+            return options {
+                externalSources = True
+            }
+
+        Flag "color" color -> do
+            option <- parseColorOption color
+            return options {
+                formatterOptions = (formatterOptions options) {
+                    foColorOption = option
+                }
+            }
+
+        Flag "sourced" _ ->
+            return options {
+                checkSpec = (checkSpec options) {
+                    csCheckSourced = True
+                }
+            }
+
+        Flag "severity" severity -> do
+            option <- parseSeverityOption severity
+            return options {
+                checkSpec = (checkSpec options) {
+                    csMinSeverity = option
+                }
+            }
+
+        Flag "wiki-link-count" countString -> do
+            count <- parseNum countString
+            return options {
+                formatterOptions = (formatterOptions options) {
+                    foWikiLinkCount = count
+                }
+            }
+
+        _ -> return options
+  where
+    die s = do
+        printErr s
+        throwError SupportFailure
+    parseNum ('S':'C':str) = parseNum str
+    parseNum num = do
+        unless (all isDigit num) $ do
+            printErr $ "Invalid number: " ++ num
+            throwError SyntaxFailure
+        return (Prelude.read num :: Integer)
+
+ioInterface options files = do
+    inputs <- mapM normalize files
+    cache <- newIORef emptyCache
+    return SystemInterface {
+        siReadFile = get cache inputs
+    }
+  where
+    emptyCache :: Map.Map FilePath String
+    emptyCache = Map.empty
+    get cache inputs file = do
+        map <- readIORef cache
+        case Map.lookup file map of
+            Just x  -> return $ Right x
+            Nothing -> fetch cache inputs file
+
+    fetch cache inputs file = do
+        ok <- allowable inputs file
+        if ok
+          then (do
+            (contents, shouldCache) <- inputFile file
+            when shouldCache $
+                modifyIORef cache $ Map.insert file contents
+            return $ Right contents
+            ) `catch` handler
+          else return $ Left (file ++ " was not specified as input (see shellcheck -x).")
+
+      where
+        handler :: IOException -> IO (Either ErrorMessage String)
+        handler ex = return . Left $ show ex
+
+    allowable inputs x =
+        if externalSources options
+        then return True
+        else do
+            path <- normalize x
+            return $ path `elem` inputs
+
+    normalize x =
+        canonicalizePath x `catch` fallback x
+      where
+        fallback :: FilePath -> IOException -> IO FilePath
+        fallback path _ = return path
+
+inputFile file = do
+    (handle, shouldCache) <-
+            if file == "-"
+            then return (stdin, True)
+            else do
+                h <- openBinaryFile file ReadMode
+                reopenable <- hIsSeekable h
+                return (h, not reopenable)
+
+    hSetBinaryMode handle True
+    contents <- decodeString <$> hGetContents handle -- closes handle
+
+    seq (length contents) $
+        return (contents, shouldCache)
+
+-- Decode a char8 string into a utf8 string, with fallback on
+-- ISO-8859-1. This avoids depending on additional libraries.
+decodeString = decode
+  where
+    decode [] = []
+    decode (c:rest) | isAscii c = c : decode rest
+    decode (c:rest) =
+        let num = (fromIntegral $ ord c) :: Int
+            next = case num of
+                _ | num >= 0xF8 -> Nothing
+                  | num >= 0xF0 -> construct (num .&. 0x07) 3 rest
+                  | num >= 0xE0 -> construct (num .&. 0x0F) 2 rest
+                  | num >= 0xC0 -> construct (num .&. 0x1F) 1 rest
+                  | True -> Nothing
+        in
+            case next of
+                Just (n, remainder) -> chr n : decode remainder
+                Nothing             -> c : decode rest
+
+    construct x 0 rest = do
+        guard $ x <= 0x10FFFF
+        return (x, rest)
+    construct x n (c:rest) =
+        let num = (fromIntegral $ ord c) :: Int in
+            if num >= 0x80 && num <= 0xBF
+            then construct ((x `shiftL` 6) .|. (num .&. 0x3f)) (n-1) rest
+            else Nothing
+    construct _ _ _ = Nothing
+
+
+verifyFiles files =
+    when (null files) $ do
+        printErr "No files specified.\n"
+        printErr $ usageInfo usageHeader options
+        throwError SyntaxFailure
+
+printVersion = do
+    putStrLn   "ShellCheck - shell script analysis tool"
+    putStrLn $ "version: " ++ shellcheckVersion
+    putStrLn   "license: GNU General Public License, version 3"
+    putStrLn   "website: https://www.shellcheck.net"

shpell.hs

@@ -1,934 +0,0 @@
-{-# LANGUAGE NoMonomorphismRestriction #-}
-
--- Shpell Check, by Vidar 'koala_man' Holen
--- Sorry about the code. It was a week's worth of hacking.
-
-import Text.Parsec
-import Text.Parsec.Pos (initialPos)
-import Debug.Trace
-import Control.Monad
-import Data.Char
-import Data.List (isInfixOf, partition, sortBy, intercalate)
-import qualified Control.Monad.State as Ms
-import Data.Maybe
-import Prelude hiding (readList)
-import System.IO
-
-
-
-backslash = char '\\'
-linefeed = char '\n'
-singleQuote = char '\''
-doubleQuote = char '"'
-variableStart = upper <|> lower <|> oneOf "_"
-variableChars = upper <|> lower <|> digit <|> oneOf "_"
-specialVariable = oneOf "@*#?-$!"
-tokenDelimiter = oneOf "&|;<> \t\n"
-quotable = oneOf "#|&;<>()$`\\ \"'\t\n"
-doubleQuotable = oneOf "\"$`"
-whitespace = oneOf " \t\n"
-linewhitespace = oneOf " \t"
-
-spacing = do
-    x <- many (many1 linewhitespace <|> (try $ string "\\\n"))
-    optional readComment
-    return $ concat x
-
-allspacing = do
-    spacing
-    x <- option False ((linefeed <|> carriageReturn) >> return True)
-    when x allspacing
-
-carriageReturn = do
-    parseNote ErrorC "Literal carriage return. Run script through tr -d '\\r' "
-    char '\r'
-
-
---------- Message/position annotation on top of user state
-data Annotated a = Annotated SourcePos [Note] a deriving (Show, Eq)
-data Note = ParseNote SourcePos Severity String | Note Severity String deriving (Show, Eq)
-data MessageStack = StackNode Note MessageStack | StackMark String SourcePos MessageStack | StackEmpty
-data ParseProblem = ParseProblem SourcePos Severity String deriving (Show, Eq)
-data OutputNote = OutputNote SourcePos Severity String deriving (Show, Eq)
-data Severity = ErrorC | WarningC | InfoC | StyleC deriving (Show, Eq, Ord)
-
-instance Functor Annotated where
-    fmap f (Annotated p n a) = Annotated p n (f a)
-
-markStack msg = do
-    pos <- getPosition
-    modifyState (StackMark msg pos)
-
-getMessages r (StackMark _ _ s) = (r, s)
-getMessages r (StackNode n s) = getMessages (n:r) s
-popStack = do
-    f <- getState
-    let (notes, stack) = getMessages [] f
-    putState stack
-    return notes
-
--- Store potential parse problems outside of parsec
-parseProblem level msg = do
-    pos <- getPosition
-    parseProblemAt pos level msg
-
-parseProblemAt pos level msg = do
-    Ms.modify ((ParseProblem pos level msg):)
-
-pushNote n = modifyState (StackNode n)
-
-parseNote l a = do
-    pos <- getPosition
-    parseNoteAt pos l a
-
-parseNoteAt pos l a = pushNote $ ParseNote pos l a
-
-
-annotated msg parser = do
-    pos <- getPosition
-    markStack msg
-    result <- parser
-    messages <- popStack
-    return $ Annotated pos messages result
-
-dropAnnotation (Annotated _ _ s) = s
-blankAnnotation pos t = Annotated pos [] t
-
-merge (Annotated pos messages result) = do
-    mapM pushNote messages
-    return result
-
-merging p = p >>= merge
-
-getOutputNotes (Annotated p notes _) = map (makeOutputNote p) notes
-
-makeOutputNote _ (ParseNote p l s) = OutputNote p l s
-makeOutputNote p (Note l s) = OutputNote p l s
-
---------- Convenient combinators
-
-thenSkip main follow = do
-    r <- main
-    optional follow
-    return r
-
-disregard x = x >> return ()
-
-reluctantlyTill p end = do -- parse p until end <|> eof matches ahead
-    (lookAhead ((disregard $ try end) <|> eof) >> return []) <|> do
-        x <- p
-        more <- reluctantlyTill p end
-        return $ x:more
-      <|> return []
-
-reluctantlyTill1 p end = do
-    notFollowedBy end
-    x <- p
-    more <- reluctantlyTill p end
-    return $ x:more
-
-attempting rest branch = do
-    ((try branch) >> rest) <|> rest
-
-wasIncluded p = option False (p >> return True)
-
--- Horrifying AST
-data Token = T_AND_IF | T_OR_IF | T_DSEMI | T_Semi | T_DLESS | T_DGREAT | T_LESSAND | T_GREATAND | T_LESSGREAT | T_DLESSDASH | T_CLOBBER | T_If | T_Then | T_Else | T_Elif | T_Fi | T_Do | T_Done | T_Case | T_Esac | T_While | T_Until | T_For | T_Lbrace | T_Rbrace | T_Lparen | T_Rparen | T_Bang | T_In  | T_NEWLINE | T_EOF | T_Less | T_Greater | T_SingleQuoted String | T_Literal String | T_NormalWord [Annotated Token] | T_DoubleQuoted [Annotated Token] | T_DollarExpansion [Token] | T_DollarBraced String | T_DollarVariable String | T_DollarArithmetic String | T_BraceExpansion String | T_IoFile Token Token | T_HereDoc Bool Bool String | T_HereString Token | T_FdRedirect String Token | T_Assignment String Token | T_Redirecting [Annotated Token] Token | T_SimpleCommand [Annotated Token] [Annotated Token] | T_Pipeline [Annotated Token] | T_Banged Token | T_AndIf (Annotated Token) (Annotated Token) | T_OrIf (Annotated Token) (Annotated Token) | T_Backgrounded Token | T_IfExpression [([Token],[Token])] [Token] | T_Subshell [Token] | T_BraceGroup [Token] | T_WhileExpression [Token] [Token] | T_UntilExpression [Token] [Token] | T_ForIn String [Token] [Token] | T_CaseExpression Token [([Token],[Token])] |T_Function String Token | T_Command (Annotated Token) | T_Script [Token]
-    deriving (Show)
-
-extractNotes' list = modifyFlag ((++) $ concatMap getOutputNotes list) >> return ()
-extractNotes (T_NormalWord list) = extractNotes' list
-extractNotes (T_DoubleQuoted list) = extractNotes' list
-extractNotes (T_Redirecting list f) = extractNotes' list
-extractNotes (T_Pipeline list) = extractNotes' list
-extractNotes (T_Command list) = extractNotes' [list]
-extractNotes (T_SimpleCommand list1 list2) = do
-    extractNotes' list1
-    extractNotes' list2
-extractNotes t = return ()
-
-
-postMessage level s = Ms.modify $ \(x, l) -> (x, Note level s : l)
-warn s = postMessage WarningC s
-inform s = postMessage InfoC s
-style s = postMessage StyleC s
-
-
-putFlag v = modifyFlag (const v) >> return ()
-getFlag = modifyFlag id
-modifyFlag f = do
-    Ms.modify $ \(x, l) -> (f x, l)
-    v <- Ms.get
-    return $ fst v
-
-
-analyzeScopes f i = mapM (analyzeScope f i)
-analyzeScope f i (Annotated pos notes t) = do
-    v <- getFlag
-    let (ret, (flag, list)) = Ms.runState (analyze f i t) (v, [])
-    putFlag flag
-    return $ Annotated pos (notes++list) ret
-
-analyze f i s@(T_NormalWord list) = do
-    f s
-    a <- analyzeScopes f i list
-    return . i $ T_NormalWord a
-
-analyze f i s@(T_DoubleQuoted list) = do
-    f s
-    a <- analyzeScopes f i list
-    return . i $ T_DoubleQuoted a
-
-analyze f i s@(T_DollarExpansion l) = do
-    f s
-    nl <- mapM (analyze f i) l
-    return . i $ T_DollarExpansion nl
-
-analyze f i s@(T_IoFile op file) = do
-    f s
-    a <- analyze f i op
-    b <- analyze f i file
-    return . i $ T_IoFile a b
-
-analyze f i s@(T_HereString word) = do
-    f s
-    a <- analyze f i word
-    return . i $ T_HereString a
-
-analyze f i s@(T_FdRedirect v t) = do
-    f s
-    a <- analyze f i t
-    return . i $ T_FdRedirect v a
-
-analyze f i s@(T_Assignment v t) = do
-    f s
-    a <- analyze f i t
-    return . i $ T_Assignment v a
-
-analyze f i s@(T_Redirecting redirs cmd) = do
-    f s
-    newRedirs <- analyzeScopes f i redirs
-    newCmd <- analyze f i $ cmd
-    return . i $ (T_Redirecting newRedirs newCmd)
-
-analyze f i s@(T_SimpleCommand vars cmds) = do
-    f s
-    a <- analyzeScopes f i vars
-    b <- analyzeScopes f i cmds
-    return . i $ T_SimpleCommand a b
-
-analyze f i s@(T_Pipeline l) = do
-    f s
-    a <- analyzeScopes f i l
-    return . i $ T_Pipeline a
-
-analyze f i s@(T_Banged l) = do
-    f s
-    a <- analyze f i l
-    return . i $ T_Banged a
-
-analyze f i s@(T_AndIf t u) = do
-    f s
-    a <- analyzeScope f i t
-    b <- analyzeScope f i u
-    return . i $ T_AndIf a b
-
-analyze f i s@(T_OrIf t u) = do
-    f s
-    a <- analyzeScope f i t
-    b <- analyzeScope f i u
-    return . i $ T_OrIf a b
-
-analyze f i s@(T_Backgrounded l) = do
-    f s
-    a <- analyze f i l
-    return . i $ T_Backgrounded a
-
-analyze f i s@(T_IfExpression conditions elses) = do
-    f s
-    newConds <- mapM (\(c, t) -> do
-                x <- mapM (analyze f i) c
-                y <- mapM (analyze f i) t
-                return (x, y)
-             ) conditions
-    newElses <- mapM (analyze f i) elses
-    return . i $ T_IfExpression newConds newElses
-
-analyze f i s@(T_Subshell l) = do
-    f s
-    a <- mapM (analyze f i) l
-    return . i $ T_Subshell a
-
-analyze f i s@(T_BraceGroup l) = do
-    f s
-    a <- mapM (analyze f i) l
-    return . i $ T_BraceGroup a
-
-analyze f i s@(T_WhileExpression c l) = do
-    f s
-    a <- mapM (analyze f i) c
-    b <- mapM (analyze f i) l
-    return . i $ T_WhileExpression a b
-
-analyze f i s@(T_UntilExpression c l) = do
-    f s
-    a <- mapM (analyze f i) c
-    b <- mapM (analyze f i) l
-    return . i $ T_UntilExpression a b
-
-analyze f i s@(T_ForIn v w l) = do
-    f s
-    a <- mapM (analyze f i) w
-    b <- mapM (analyze f i) l
-    return . i $ T_ForIn v a b
-
-analyze f i s@(T_CaseExpression word cases) = do
-    f s
-    newWord <- analyze f i word
-    newCases <- mapM (\(c, t) -> do
-                x <- mapM (analyze f i) c
-                y <- mapM (analyze f i) t
-                return (x, y)
-             ) cases
-    return . i $ T_CaseExpression newWord newCases
-
-analyze f i s@(T_Script l) = do
-    f s
-    a <- mapM (analyze f i) l
-    return . i $ T_Script a
-
-analyze f i s@(T_Function name body) = do
-    f s
-    a <- analyze f i body
-    return . i $ T_Function name a
-
-analyze f i s@(T_Command c) = do
-    f s
-    a <- analyzeScope f i c
-    return . i $ T_Command a
-
-analyze f i t = do
-    f t
-    return . i $ t
-
-doAnalysis f t = fst $ Ms.runState (analyze f id t) ((), [])
-explore f d t = fst . snd $ Ms.runState (analyze f id t) (d, [])
-transform i t = fst $ Ms.runState (analyze (const $ return ()) i t) ((), [])
-
-findNotes t = explore extractNotes [] t
-sortNotes l = sortBy compareNotes l
-compareNotes (OutputNote pos1 level1 _) (OutputNote pos2 level2 _) = compare (pos1, level1) (pos2, level2)
-findParseNotes l = map (\(ParseProblem p level s) -> OutputNote p level s) l
---   T_UntilExpression [Token] [Token] | T_ForIn String [Token] [Token]
-
-getNotes s =
-    case rp readScript s of
-        (Right x, p) -> sortNotes $ (findNotes $ doAllAnalysis x) ++ (findParseNotes p)
-        (Left _, p) -> sortNotes $ (OutputNote (initialPos "-") ErrorC "Parsing failed"):(findParseNotes p)
-
-readComment = do
-    char '#'
-    anyChar `reluctantlyTill` linefeed
-
-readNormalWord = do
-    x <- many1 readNormalWordPart
-    return $ T_NormalWord x
-
-readNormalWordPart = readSingleQuoted <|> readDoubleQuoted <|> readDollar <|> readBraced <|> readBackTicked <|> (annotated "normal literal" $ readNormalLiteral)
-
-readSingleQuoted = annotated "single quoted string" $ do
-    singleQuote
-    s <- readSingleQuotedPart `reluctantlyTill` singleQuote
-    singleQuote <?> "End single quoted string"
-
-    let string = concat s
-    return (T_SingleQuoted string) `attempting` do
-        x <- lookAhead anyChar
-        when (isAlpha x && isAlpha (last string)) $ parseProblem WarningC "This apostrophe terminated the single quoted string."
-
-readSingleQuotedLiteral = do
-    singleQuote
-    strs <- many1 readSingleQuotedPart
-    singleQuote
-    return $ concat strs
-
-readSingleQuotedPart =
-    readSingleEscaped
-    <|> anyChar `reluctantlyTill1` (singleQuote <|> backslash)
-
-readBackTicked = annotated "backtick expansion" $ do
-    parseNote StyleC "`..` style expansion is deprecated, use $(..) instead if you want my help"
-    pos <- getPosition
-    char '`'
-    f <- readGenericLiteral (char '`')
-    char '`' `attempting` (eof >> parseProblemAt pos ErrorC "Can't find terminating backtick for this one")
-    return $ T_Literal f
-
-
-readDoubleQuoted = annotated "double quoted string" $ do
-    doubleQuote
-    x <- many doubleQuotedPart
-    doubleQuote <?> "End double quoted"
-    return $ T_DoubleQuoted x
-
-doubleQuotedPart = readDoubleLiteral <|> readDollar <|> readBackTicked
-
-readDoubleQuotedLiteral = do
-    doubleQuote
-    x <- readDoubleLiteral
-    doubleQuote
-    return $ dropAnnotation x
-
-readDoubleLiteral = annotated "double literal" $ do
-    s <- many1 readDoubleLiteralPart
-    return $ T_Literal (concat s)
-
-readDoubleLiteralPart = do
-    x <- (readDoubleEscaped <|> (anyChar >>= \x -> return [x])) `reluctantlyTill1` doubleQuotable
-    return $ concat x
-
-readNormalLiteral = do
-    s <- many1 readNormalLiteralPart
-    return $ T_Literal (concat s)
-
-readNormalLiteralPart = do
-    readNormalEscaped <|> (anyChar `reluctantlyTill1` quotable)
-
-readNormalEscaped = do
-    backslash
-    pos <- getPosition
-    do
-        next <- (quotable <|> oneOf "?*[]")
-        return $ if next == '\n' then "" else [next]
-      <|>
-        do
-            next <- anyChar <?> "No character after \\"
-            parseNoteAt pos WarningC $ "This character doesn't need escaping here, the \\ is ignored"
-            return [next]
-
-readSingleEscaped = do
-    s <- backslash
-    let attempt level p msg = do { try $ parseNote level msg; x <- p; return [s,x]; }
-
-    do {
-        x <- singleQuote;
-        parseProblem InfoC "Are you trying to escape a single quote? echo 'You'\\''re doing it wrong'.";
-        return [s,x];
-    }
-        <|> attempt InfoC linefeed "You don't break lines with \\ in single quotes, it results in literal backslash-linefeed."
-        <|> do
-            x <- anyChar
-            return [s,x]
-
-
-readDoubleEscaped = do
-    bs <- backslash
-    (linefeed >> return "")
-        <|> (doubleQuotable >>= return . return)
-        <|> (anyChar >>= (return . \x -> [bs, x]))
-
-
-readGenericLiteral endExp = do
-    strings <- many (readGenericEscaped <|> anyChar `reluctantlyTill1` endExp)
-    return $ concat strings
-
-readGenericLiteral1 endExp = do
-    strings <- many1 (readGenericEscaped <|> anyChar `reluctantlyTill1` endExp)
-    return $ concat strings
-
-readGenericEscaped = do
-    backslash
-    x <- anyChar
-    return $ if x == '\n' then [] else [x]
-
-readBraced = annotated "{1,2..3} expression" $ try $ do
-    let strip (T_Literal s) = return ("\"" ++ s ++ "\"")
-    char '{'
-    str <- many1 ((readDoubleQuotedLiteral >>= (strip )) <|> readGenericLiteral1 (oneOf "}" <|> whitespace))
-    char '}'
-    return $ T_BraceExpansion $ concat str
-
-readDollar = readDollarArithmetic <|> readDollarBraced <|> readDollarExpansion <|> readDollarVariable <|> readDollarLonely
-
-
-readParenLiteralHack = do
-    strs <- ((anyChar >>= \x -> return [x]) <|> readParenHack) `reluctantlyTill1` (string "))")
-    return $ concat strs
-
-readParenHack = do
-    char '('
-    x <- many anyChar
-    char ')'
-    return $ "(" ++ x ++ ")"
-
-readDollarArithmetic = annotated "$(( )) expression" $ do
-    try (string "$((")
-    -- TODO
-    str <- readParenLiteralHack
-    string "))"
-    return (T_DollarArithmetic str)
-
-readDollarBraced = annotated "${ } expression" $ do
-    try (string "${")
-    -- TODO
-    str <- readGenericLiteral (char '}')
-    char '}' <?> "matching }"
-    return $ (T_DollarBraced str)
-
-readDollarExpansion = annotated "$( )" $ do
-    try (string "$(")
-    cmds <- readCompoundList
-    char ')'
-    return $ (T_DollarExpansion cmds)
-
-readDollarVariable = annotated "$variable" $ do
-    let singleCharred p = do
-        n <- p
-        return (T_DollarVariable [n]) `attempting` do
-            pos <- getPosition
-            num <- lookAhead $ many1 p
-            parseNoteAt pos ErrorC $ "$" ++ (n:num) ++ " is equivalent to ${" ++ [n] ++ "}"++ num
-
-    let positional = singleCharred digit
-    let special = singleCharred specialVariable
-
-    let regular = do
-        name <- readVariableName
-        return $ T_DollarVariable (name)
-
-    char '$'
-    positional <|> special <|> regular
-
-readVariableName = do
-    f <- variableStart
-    rest <- many variableChars
-    return (f:rest)
-
-readDollarLonely = annotated "lonely $" $ do
-    parseNote ErrorC "$ is not used specially and should therefore be escaped"
-    char '$'
-    return $ T_Literal "$"
-
-readHereDoc = annotated "here document" $ do
-    let stripLiteral (T_Literal x) = x
-        stripLiteral (T_SingleQuoted x) = x
-    try $ string "<<"
-    dashed <- (char '-' >> return True) <|> return False
-    tokenPosition <- getPosition
-    spacing
-    (quoted, endToken) <- (readNormalLiteral >>= (\x -> return (False, stripLiteral x)) )
-                            <|> (readDoubleQuotedLiteral >>= return . (\x -> (True, stripLiteral x)))
-                            <|> (readSingleQuotedLiteral >>= return . (\x -> (True, x)))
-    spacing
-
-    hereInfo <- anyChar `reluctantlyTill` (linefeed >> spacing >> (string endToken) >> (disregard whitespace <|> eof))
-
-    do
-        linefeed
-        spaces <- spacing
-        verifyHereDoc dashed quoted spaces hereInfo
-        token <- string endToken
-        return $ T_FdRedirect "" $ T_HereDoc dashed quoted hereInfo
-     `attempting` (eof >> debugHereDoc tokenPosition endToken hereInfo)
-
-verifyHereDoc dashed quoted spacing hereInfo = do
-    when (not dashed && spacing /= "") $ parseNote ErrorC "When using << instead of <<-, the end tokens can't be indented"
-    when (dashed && filter (/= '\t') spacing /= "" ) $ parseNote ErrorC "When using <<-, you can only indent with tabs"
-    return ()
-
-debugHereDoc pos endToken doc =
-    if endToken `isInfixOf` doc
-        then parseProblemAt pos ErrorC (endToken ++ " was part of the here document, but not by itself at the start of the line")
-        else if (map toLower endToken) `isInfixOf` (map toLower doc)
-            then parseProblemAt pos ErrorC (endToken ++ " appears in the here document, but with different case")
-            else parseProblemAt pos ErrorC ("Couldn't find end token `" ++ endToken ++ "' in the here document ")
-
-
-readFilename = readNormalWord
-readIoFileOp = choice [g_LESSAND, g_GREATAND, g_DGREAT, g_LESSGREAT, g_CLOBBER, string "<" >> return T_Less, string ">" >> return T_Greater ]
-readIoFile = do
-    op <- readIoFileOp
-    spacing
-    file <- readFilename
-    return $ T_FdRedirect "" $ T_IoFile op file
-readIoNumber = try $ do
-    x <- many1 digit
-    lookAhead readIoFileOp
-    return x
-readIoNumberRedirect = annotated "fd io redirect" $ do
-    n <- readIoNumber
-    op <- merging readHereString <|> merging readHereDoc <|> readIoFile
-    let actualOp = case op of T_FdRedirect "" x -> x
-    spacing
-    return $ T_FdRedirect n actualOp
-
-readIoRedirect = annotated "io redirect" $ choice [ merging readIoNumberRedirect, merging readHereString, merging readHereDoc, readIoFile ] `thenSkip` spacing
-
-readRedirectList = many1 readIoRedirect
-
-readHereString = annotated "here string" $ do
-    try $ string "<<<"
-    spacing
-    word <- readNormalWord
-    return $ T_FdRedirect "" $ T_HereString word
-
-readNewlineList = many1 ((newline <|> carriageReturn) `thenSkip` spacing)
-readLineBreak = optional readNewlineList
-
-readSeparatorOp = do
-    notFollowedBy (g_AND_IF <|> g_DSEMI)
-    f <- char ';' <|> char '&'
-    spacing
-    return f
-
-readSequentialSep = (disregard $ g_Semi >> readLineBreak) <|> (disregard readNewlineList)
-readSeparator =
-    do
-        separator <- readSeparatorOp
-        readLineBreak
-        return separator
-     <|>
-        do
-            readNewlineList
-            return '\n'
-
-makeSimpleCommand tokens =
-    let (assignment, rest) = partition (\x -> case dropAnnotation x of T_Assignment _ _ -> True; _ -> False) tokens
-    in let (redirections, rest2) = partition (\x -> case dropAnnotation x of T_FdRedirect _ _ -> True; _ -> False) rest
-       in T_Redirecting redirections $ T_SimpleCommand assignment rest2
-
-readSimpleCommand = annotated "simple command" $ do
-    prefix <- option [] readCmdPrefix
-    cmd <- option [] $ do { f <- annotated "command name" readCmdName; return [f]; }
-    when (null prefix && null cmd) $ fail "No command"
-    if null cmd
-        then return $ makeSimpleCommand prefix
-        else do
-            suffix <- option [] readCmdSuffix
-            return $ makeSimpleCommand (prefix ++ cmd ++ suffix)
-
-readPipeline = annotated "Pipeline" $ do
-    notFollowedBy $ try readKeyword
-    do
-        g_Bang `thenSkip` spacing
-        pipe <- readPipeSequence
-        return $ T_Banged pipe
-      <|> do
-        readPipeSequence
-
-readAndOr = (flip (>>=)) (return . T_Command) $ chainr1 readPipeline $ do
-    pos <- getPosition
-    op <- g_AND_IF <|> g_OR_IF
-    readLineBreak
-    return $ \a b ->
-                blankAnnotation pos $
-                     case op of T_AND_IF -> T_AndIf a b
-                                T_OR_IF  -> T_OrIf a b
-
-readTerm = do
-    m <- readAndOr
-    readTerm' m
-
-readTerm' current =
-    do
-        sep <- readSeparator
-        more <- (option T_EOF $ readAndOr)
-        case more of T_EOF -> return [transformWithSeparator sep current]
-                     _     -> do
-                                list <- readTerm' more
-                                return $ (transformWithSeparator sep current : list)
-      <|>
-        return [current]
-
-transformWithSeparator '&' = T_Backgrounded
-transformWithSeparator _  = id
-
-
-readPipeSequence = do
-    list <- readCommand `sepBy1` (readPipe `thenSkip` (spacing >> readLineBreak))
-    spacing
-    return $ T_Pipeline list
-
-readPipe = do
-    notFollowedBy g_OR_IF
-    char '|' `thenSkip` spacing
-
-readCommand = (readCompoundCommand <|> readSimpleCommand)
-
-readCmdName = do
-    f <- readNormalWord
-    spacing
-    return f
-
-readCmdWord = do
-    f <- readNormalWord
-    spacing
-    return f
-
-readIfClause = annotated "if statement" $ do
-    (condition, action) <- readIfPart
-    elifs <- many readElifPart
-    elses <- option [] readElsePart
-    g_Fi
-    return $ T_IfExpression ((condition, action):elifs) elses
-
-readIfPart = do
-    g_If
-    allspacing
-    condition <- readTerm
-    g_Then
-    allspacing
-    action <- readTerm
-    return (condition, action)
-
-readElifPart = do
-    g_Elif
-    allspacing
-    condition <- readTerm
-    g_Then
-    allspacing
-    action <- readTerm
-    return (condition, action)
-
-readElsePart = do
-    g_Else
-    allspacing
-    readTerm
-
-readSubshell = annotated "subshell group" $ do
-    char '('
-    allspacing
-    list <- readCompoundList
-    allspacing
-    char ')'
-    return $ T_Subshell list
-
-readBraceGroup = annotated "brace group" $ do
-    char '{'
-    allspacing
-    list <- readTerm
-    allspacing
-    char '}'
-    return $ T_BraceGroup list
-
-readWhileClause = annotated "while loop" $ do
-    g_While
-    condition <- readTerm
-    statements <- readDoGroup
-    return $ T_WhileExpression condition statements
-
-readUntilClause = annotated "until loop" $ do
-    g_Until
-    condition <- readTerm
-    statements <- readDoGroup
-    return $ T_UntilExpression condition statements
-
-readDoGroup = do
-    pos <- getPosition
-    g_Do
-    allspacing
-    (eof >> return []) <|>
-        do
-            commands <- readCompoundList
-            disregard g_Done <|> eof -- stunted support
-            return commands
-          <|> do
-            parseProblemAt pos ErrorC "Can't find the 'done' for this 'do'"
-            fail "No done"
-
-readForClause = annotated "for loop" $ do
-    g_For
-    spacing
-    name <- readVariableName
-    allspacing
-    values <- readInClause <|> (readSequentialSep >> return [])
-    group <- readDoGroup <|> (allspacing >> eof >> return []) -- stunted support
-    return $ T_ForIn name values group
-
-readInClause = do
-    g_In
-    things <- (readCmdWord) `reluctantlyTill`
-                (disregard (g_Semi) <|> disregard linefeed <|> disregard g_Do)
-
-    do {
-        lookAhead (g_Do);
-        parseNote ErrorC "You need a line feed or semicolon before the 'do' (in Bash)";
-    } <|> do {
-        optional $ g_Semi;
-        disregard allspacing;
-    }
-
-    return things
-
-readCaseClause = annotated "case statement" $ do
-    g_Case
-    word <- readNormalWord
-    spacing
-    g_In
-    readLineBreak
-    list <- readCaseList
-    g_Esac
-    return $ T_CaseExpression word list
-
-readCaseList = many readCaseItem
-
-readCaseItem = do
-    notFollowedBy g_Esac
-    optional g_Lparen
-    spacing
-    pattern <- readPattern
-    g_Rparen
-    readLineBreak
-    list <- ((lookAhead g_DSEMI >> return []) <|> readCompoundList)
-    (g_DSEMI <|> lookAhead (readLineBreak >> g_Esac))
-    readLineBreak
-    return (pattern, list)
-
-readFunctionDefinition = annotated "function definition" $ do
-    name <- try readFunctionSignature
-    allspacing
-    (disregard (lookAhead g_Lbrace) <|> parseProblem ErrorC "Expected a { to open the function definition")
-    group <- merging readBraceGroup
-    return $ T_Function name group
-
-
-readFunctionSignature = do
-    (optional $ try (string "function " >> parseNote StyleC "Don't use 'function' in front of function definitions"))
-    name <- readVariableName
-    spacing
-    g_Lparen
-    g_Rparen
-    return name
-
-
-readPattern = (readNormalWord `thenSkip` spacing) `sepBy1` (char '|' `thenSkip` spacing)
-
-
-readCompoundCommand = annotated "compound command" $ do
-    cmd <- merging $ choice [ readBraceGroup, readSubshell, readWhileClause, readUntilClause, readIfClause, readForClause, readCaseClause, readFunctionDefinition]
-    spacing
-    redirs <- many readIoRedirect
-    return $ T_Redirecting redirs $ cmd
-
-
-readCompoundList = readTerm
-
-readCmdPrefix = many1 (readIoRedirect <|> readAssignmentWord)
-readCmdSuffix = many1 (readIoRedirect <|> annotated "normal word" readCmdWord)
-
-readAssignmentWord = annotated "assignment" $ try $ do
-    optional (char '$' >> parseNote ErrorC "Don't use $ on the left side of assignments")
-    variable <- readVariableName
-    space <- spacing
-    pos <- getPosition
-    char '='
-    space2 <- spacing
-    value <- readNormalWord
-    spacing
-    when (space ++ space2 /= "") $ parseNoteAt pos ErrorC "Don't put spaces around the = in assignments"
-    return $ T_Assignment variable value
-
-
-tryToken s t = try (string s >> spacing >> return t)
-tryWordToken s t = tryParseWordToken (string s) t `thenSkip` spacing
-tryParseWordToken parser t = try (parser >> (lookAhead (eof <|> disregard whitespace))) >> return t
-
-g_AND_IF = tryToken "&&" T_AND_IF
-g_OR_IF = tryToken "||" T_OR_IF
-g_DSEMI = tryToken ";;" T_DSEMI
-g_DLESS = tryToken "<<" T_DLESS
-g_DGREAT = tryToken ">>" T_DGREAT
-g_LESSAND = tryToken "<&" T_LESSAND
-g_GREATAND = tryToken ">&" T_GREATAND
-g_LESSGREAT = tryToken "<>" T_LESSGREAT
-g_DLESSDASH = tryToken "<<-" T_DLESSDASH
-g_CLOBBER = tryToken ">|" T_CLOBBER
-g_OPERATOR = g_AND_IF <|> g_OR_IF <|> g_DSEMI <|> g_DLESSDASH <|> g_DLESS <|> g_DGREAT <|> g_LESSAND <|> g_GREATAND <|> g_LESSGREAT
-
-g_If = tryWordToken "if" T_If
-g_Then = tryWordToken "then" T_Then
-g_Else = tryWordToken "else" T_Else
-g_Elif = tryWordToken "elif" T_Elif
-g_Fi = tryWordToken "fi" T_Fi
-g_Do = tryWordToken "do" T_Do
-g_Done = tryWordToken "done" T_Done
-g_Case = tryWordToken "case" T_Case
-g_Esac = tryWordToken "esac" T_Esac
-g_While = tryWordToken "while" T_While
-g_Until = tryWordToken "until" T_Until
-g_For = tryWordToken "for" T_For
-g_In = tryWordToken "in" T_In
-g_Lbrace = tryWordToken "{" T_Lbrace
-g_Rbrace = tryWordToken "}" T_Rbrace
-
-g_Lparen = tryToken "(" T_Lparen
-g_Rparen = tryToken ")" T_Rparen
-g_Bang = tryToken "!" T_Bang
-
-g_Semi = do
-    notFollowedBy g_DSEMI
-    tryToken ";" T_Semi
-
-readKeyword = choice [ g_Then, g_Else, g_Elif, g_Fi, g_Do, g_Done, g_Esac, g_Rbrace, g_Rparen, g_DSEMI ]
-
-ifParse p t f = do
-    (lookAhead (try p) >> t) <|> f
-
-wtf = do
-    x <- many anyChar
-    parseProblem ErrorC x
-
-readScript = do
-    do {
-        allspacing;
-        commands <- readTerm;
-        eof <|> (parseProblem WarningC "Stopping here, because I can't parse this command");
-        return $ T_Script commands;
-    } <|> do {
-        parseProblem WarningC "Couldn't read any commands";
-        wtf;
-        return T_EOF;
-    }
-
-shpell s = rp readScript s
-rp p s = Ms.runState (runParserT p StackEmpty "-" s) []
-
--------- Destructively simplify AST
-
-simplify (T_Redirecting [] t) = t
-simplify (T_Pipeline [x]) = dropAnnotation x
-simplify (T_NormalWord [x]) = dropAnnotation x
-simplify t = t
-
--------- Analytics
-doAllAnalysis t = foldl (\v f -> doAnalysis f v) t checks
-
-getAst s = case rp readScript s of (Right parsed, _) -> parsed
-getAst2 s = case rp readScript s of (Right parsed, _) -> transform simplify parsed
-lol (Right x, _) = x
-
-deadSimple (T_NormalWord l) = [concat (concatMap (deadSimple . dropAnnotation) l)]
-deadSimple (T_DoubleQuoted l) = ["\"" ++(concat (concatMap (deadSimple . dropAnnotation) l)) ++ "\""]
-deadSimple (T_SingleQuoted s) = [s]
-deadSimple (T_DollarVariable _) = ["${VAR}"]
-deadSimple (T_DollarBraced _) = ["${VAR}"]
-deadSimple (T_DollarArithmetic _) = ["${VAR}"]
-deadSimple (T_DollarExpansion _) = ["${VAR}"]
-deadSimple (T_Literal x) = [x]
-deadSimple (T_SimpleCommand vars words) = concatMap (deadSimple . dropAnnotation) words
-deadSimple (T_Redirecting _ foo) = deadSimple foo
-deadSimple _ = []
-
-
-checks = [checkUuoc]
-checkUuoc (T_Pipeline ((Annotated _ _ x):_:_)) = case (deadSimple x) of ["cat", _] -> style "UUOC: Instead of 'cat a | b', use 'b < a'"
-                                                                        _ -> return ()
-checkUuoc _ = return ()
-
-
-main = do
-    s <- getContents
---    case rp readScript s of (Right parsed, _) -> putStrLn . show $ transform simplify parsed
---                            (Left x, y) -> putStrLn $ "Can't parse: " ++ (show (x,y))
-
-    mapM (putStrLn . show) $ getNotes s

snap/snapcraft.yaml

@@ -0,0 +1,53 @@
+name: shellcheck
+summary: A shell script static analysis tool
+description: |
+  ShellCheck is a GPLv3 tool that gives warnings and suggestions for bash/sh
+  shell scripts.
+
+  The goals of ShellCheck are
+
+  - To point out and clarify typical beginner's syntax issues that cause a
+    shell to give cryptic error messages.
+
+  - To point out and clarify typical intermediate level semantic problems that
+    cause a shell to behave strangely and counter-intuitively.
+
+  - To point out subtle caveats, corner cases and pitfalls that may cause an
+    advanced user's otherwise working script to fail under future
+    circumstances.
+
+  By default ShellCheck can only check non-hidden files under /home, to make 
+  ShellCheck be able to check files under /media and /run/media you must
+  connect it to the `removable-media` interface manually:
+
+      # snap connect shellcheck:removable-media
+  
+version: git
+grade: devel
+confinement: strict
+
+apps:
+  shellcheck:
+    command: usr/bin/shellcheck
+    plugs: [home, removable-media]
+
+parts:
+  shellcheck:
+    plugin: dump
+    source: ./
+    build-packages:
+      - cabal-install
+      - squid3
+    build: |
+      # See comments in .snapsquid.conf
+      [ "$http_proxy" ] && {
+        squid3 -f .snapsquid.conf
+        export http_proxy="http://localhost:8888"
+        sleep 3
+      }
+      cabal sandbox init
+      cabal update || cat /var/log/squid/*
+      cabal install -j
+    install: |
+      install -d $SNAPCRAFT_PART_INSTALL/usr/bin
+      install .cabal-sandbox/bin/shellcheck $SNAPCRAFT_PART_INSTALL/usr/bin

src/ShellCheck/AST.hs

@@ -0,0 +1,389 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.AST where
+
+import Control.Monad.Identity
+import Text.Parsec
+import qualified ShellCheck.Regex as Re
+import Prelude hiding (id)
+
+newtype Id = Id Int deriving (Show, Eq, Ord)
+
+data Quoted = Quoted | Unquoted deriving (Show, Eq)
+data Dashed = Dashed | Undashed deriving (Show, Eq)
+data AssignmentMode = Assign | Append deriving (Show, Eq)
+newtype FunctionKeyword = FunctionKeyword Bool deriving (Show, Eq)
+newtype FunctionParentheses = FunctionParentheses Bool deriving (Show, Eq)
+data CaseType = CaseBreak | CaseFallThrough | CaseContinue deriving (Show, Eq)
+
+newtype Root = Root Token
+data Token =
+    TA_Binary Id String Token Token
+    | TA_Assignment Id String Token Token
+    | TA_Variable Id String [Token]
+    | TA_Expansion Id [Token]
+    | TA_Sequence Id [Token]
+    | TA_Trinary Id Token Token Token
+    | TA_Unary Id String Token
+    | TC_And Id ConditionType String Token Token
+    | TC_Binary Id ConditionType String Token Token
+    | TC_Group Id ConditionType Token
+    | TC_Nullary Id ConditionType Token
+    | TC_Or Id ConditionType String Token Token
+    | TC_Unary Id ConditionType String Token
+    | TC_Empty Id ConditionType
+    | T_AND_IF Id
+    | T_AndIf Id Token Token
+    | T_Arithmetic Id Token
+    | T_Array Id [Token]
+    | T_IndexedElement Id [Token] Token
+    -- Store the index as string, and parse as arithmetic or string later
+    | T_UnparsedIndex Id SourcePos String
+    | T_Assignment Id AssignmentMode String [Token] Token
+    | T_Backgrounded Id Token
+    | T_Backticked Id [Token]
+    | T_Bang Id
+    | T_Banged Id Token
+    | T_BraceExpansion Id [Token]
+    | T_BraceGroup Id [Token]
+    | T_CLOBBER Id
+    | T_Case Id
+    | T_CaseExpression Id Token [(CaseType, [Token], [Token])]
+    | T_Condition Id ConditionType Token
+    | T_DGREAT Id
+    | T_DLESS Id
+    | T_DLESSDASH Id
+    | T_DSEMI Id
+    | T_Do Id
+    | T_DollarArithmetic Id Token
+    | T_DollarBraced Id Token
+    | T_DollarBracket Id Token
+    | T_DollarDoubleQuoted Id [Token]
+    | T_DollarExpansion Id [Token]
+    | T_DollarSingleQuoted Id String
+    | T_DollarBraceCommandExpansion Id [Token]
+    | T_Done Id
+    | T_DoubleQuoted Id [Token]
+    | T_EOF Id
+    | T_Elif Id
+    | T_Else Id
+    | T_Esac Id
+    | T_Extglob Id String [Token]
+    | T_FdRedirect Id String Token
+    | T_Fi Id
+    | T_For Id
+    | T_ForArithmetic Id Token Token Token [Token]
+    | T_ForIn Id String [Token] [Token]
+    | T_Function Id FunctionKeyword FunctionParentheses String Token
+    | T_GREATAND Id
+    | T_Glob Id String
+    | T_Greater Id
+    | T_HereDoc Id Dashed Quoted String [Token]
+    | T_HereString Id Token
+    | T_If Id
+    | T_IfExpression Id [([Token],[Token])] [Token]
+    | T_In  Id
+    | T_IoFile Id Token Token
+    | T_IoDuplicate Id Token String
+    | T_LESSAND Id
+    | T_LESSGREAT Id
+    | T_Lbrace Id
+    | T_Less Id
+    | T_Literal Id String
+    | T_Lparen Id
+    | T_NEWLINE Id
+    | T_NormalWord Id [Token]
+    | T_OR_IF Id
+    | T_OrIf Id Token Token
+    | T_ParamSubSpecialChar Id String -- e.g. '%' in ${foo%bar}  or '/' in ${foo/bar/baz}
+    | T_Pipeline Id [Token] [Token] -- [Pipe separators] [Commands]
+    | T_ProcSub Id String [Token]
+    | T_Rbrace Id
+    | T_Redirecting Id [Token] Token
+    | T_Rparen Id
+    | T_Script Id String [Token]
+    | T_Select Id
+    | T_SelectIn Id String [Token] [Token]
+    | T_Semi Id
+    | T_SimpleCommand Id [Token] [Token]
+    | T_SingleQuoted Id String
+    | T_Subshell Id [Token]
+    | T_Then Id
+    | T_Until Id
+    | T_UntilExpression Id [Token] [Token]
+    | T_While Id
+    | T_WhileExpression Id [Token] [Token]
+    | T_Annotation Id [Annotation] Token
+    | T_Pipe Id String
+    | T_CoProc Id (Maybe String) Token
+    | T_CoProcBody Id Token
+    | T_Include Id Token
+    | T_SourceCommand Id Token Token
+    deriving (Show)
+
+data Annotation =
+    DisableComment Integer
+    | SourceOverride String
+    | ShellOverride String
+    deriving (Show, Eq)
+data ConditionType = DoubleBracket | SingleBracket deriving (Show, Eq)
+
+-- This is an abomination.
+tokenEquals :: Token -> Token -> Bool
+tokenEquals a b = kludge a == kludge b
+    where kludge s = Re.subRegex (Re.mkRegex "\\(Id [0-9]+\\)") (show s) "(Id 0)"
+
+instance Eq Token where
+    (==) = tokenEquals
+
+analyze :: Monad m => (Token -> m ()) -> (Token -> m ()) -> (Token -> m Token) -> Token -> m Token
+analyze f g i =
+    round
+  where
+    round t = do
+        f t
+        newT <- delve t
+        g t
+        i newT
+    roundAll = mapM round
+
+    dl l v = do
+        x <- roundAll l
+        return $ v x
+    dll l m v = do
+        x <- roundAll l
+        y <- roundAll m
+        return $ v x y
+    d1 t v = do
+        x <- round t
+        return $ v x
+    d2 t1 t2 v = do
+        x <- round t1
+        y <- round t2
+        return $ v x y
+
+    delve (T_NormalWord id list) = dl list $ T_NormalWord id
+    delve (T_DoubleQuoted id list) = dl list $ T_DoubleQuoted id
+    delve (T_DollarDoubleQuoted id list) = dl list $ T_DollarDoubleQuoted id
+    delve (T_DollarExpansion id list) = dl list $ T_DollarExpansion id
+    delve (T_DollarBraceCommandExpansion id list) = dl list $ T_DollarBraceCommandExpansion id
+    delve (T_BraceExpansion id list) = dl list $ T_BraceExpansion id
+    delve (T_Backticked id list) = dl list $ T_Backticked id
+    delve (T_DollarArithmetic id c) = d1 c $ T_DollarArithmetic id
+    delve (T_DollarBracket id c) = d1 c $ T_DollarBracket id
+    delve (T_IoFile id op file) = d2 op file $ T_IoFile id
+    delve (T_IoDuplicate id op num) = d1 op $ \x -> T_IoDuplicate id x num
+    delve (T_HereString id word) = d1 word $ T_HereString id
+    delve (T_FdRedirect id v t) = d1 t $ T_FdRedirect id v
+    delve (T_Assignment id mode var indices value) = do
+        a <- roundAll indices
+        b <- round value
+        return $ T_Assignment id mode var a b
+    delve (T_Array id t) = dl t $ T_Array id
+    delve (T_IndexedElement id indices t) = do
+        a <- roundAll indices
+        b <- round t
+        return $ T_IndexedElement id a b
+    delve (T_Redirecting id redirs cmd) = do
+        a <- roundAll redirs
+        b <- round cmd
+        return $ T_Redirecting id a b
+    delve (T_SimpleCommand id vars cmds) = dll vars cmds $ T_SimpleCommand id
+    delve (T_Pipeline id l1 l2) = dll l1 l2 $ T_Pipeline id
+    delve (T_Banged id l) = d1 l $ T_Banged id
+    delve (T_AndIf id t u) = d2 t u $ T_AndIf id
+    delve (T_OrIf id t u) = d2 t u $ T_OrIf id
+    delve (T_Backgrounded id l) = d1 l $ T_Backgrounded id
+    delve (T_Subshell id l) = dl l $ T_Subshell id
+    delve (T_ProcSub id typ l) = dl l $ T_ProcSub id typ
+    delve (T_Arithmetic id c) = d1 c $ T_Arithmetic id
+    delve (T_IfExpression id conditions elses) = do
+        newConds <- mapM (\(c, t) -> do
+                            x <- mapM round c
+                            y <- mapM round t
+                            return (x,y)
+                    ) conditions
+        newElses <- roundAll elses
+        return $ T_IfExpression id newConds newElses
+    delve (T_BraceGroup id l) = dl l $ T_BraceGroup id
+    delve (T_WhileExpression id c l) = dll c l $ T_WhileExpression id
+    delve (T_UntilExpression id c l) = dll c l $ T_UntilExpression id
+    delve (T_ForIn id v w l) = dll w l $ T_ForIn id v
+    delve (T_SelectIn id v w l) = dll w l $ T_SelectIn id v
+    delve (T_CaseExpression id word cases) = do
+        newWord <- round word
+        newCases <- mapM (\(o, c, t) -> do
+                            x <- mapM round c
+                            y <- mapM round t
+                            return (o, x,y)
+                        ) cases
+        return $ T_CaseExpression id newWord newCases
+
+    delve (T_ForArithmetic id a b c group) = do
+        x <- round a
+        y <- round b
+        z <- round c
+        list <- mapM round group
+        return $ T_ForArithmetic id x y z list
+
+    delve (T_Script id s l) = dl l $ T_Script id s
+    delve (T_Function id a b name body) = d1 body $ T_Function id a b name
+    delve (T_Condition id typ token) = d1 token $ T_Condition id typ
+    delve (T_Extglob id str l) = dl l $ T_Extglob id str
+    delve (T_DollarBraced id op) = d1 op $ T_DollarBraced id
+    delve (T_HereDoc id d q str l) = dl l $ T_HereDoc id d q str
+
+    delve (TC_And id typ str t1 t2) = d2 t1 t2 $ TC_And id typ str
+    delve (TC_Or id typ str t1 t2) = d2 t1 t2 $ TC_Or id typ str
+    delve (TC_Group id typ token) = d1 token $ TC_Group id typ
+    delve (TC_Binary id typ op lhs rhs) = d2 lhs rhs $ TC_Binary id typ op
+    delve (TC_Unary id typ op token) = d1 token $ TC_Unary id typ op
+    delve (TC_Nullary id typ token) = d1 token $ TC_Nullary id typ
+
+    delve (TA_Binary id op t1 t2) = d2 t1 t2 $ TA_Binary id op
+    delve (TA_Assignment id op t1 t2) = d2 t1 t2 $ TA_Assignment id op
+    delve (TA_Unary id op t1) = d1 t1 $ TA_Unary id op
+    delve (TA_Sequence id l) = dl l $ TA_Sequence id
+    delve (TA_Trinary id t1 t2 t3) = do
+        a <- round t1
+        b <- round t2
+        c <- round t3
+        return $ TA_Trinary id a b c
+    delve (TA_Expansion id t) = dl t $ TA_Expansion id
+    delve (TA_Variable id str t) = dl t $ TA_Variable id str
+    delve (T_Annotation id anns t) = d1 t $ T_Annotation id anns
+    delve (T_CoProc id var body) = d1 body $ T_CoProc id var
+    delve (T_CoProcBody id t) = d1 t $ T_CoProcBody id
+    delve (T_Include id script) = d1 script $ T_Include id
+    delve (T_SourceCommand id includer t_include) = d2 includer t_include $ T_SourceCommand id
+    delve t = return t
+
+getId :: Token -> Id
+getId t = case t of
+        T_AND_IF id  -> id
+        T_OR_IF id  -> id
+        T_DSEMI id  -> id
+        T_Semi id  -> id
+        T_DLESS id  -> id
+        T_DGREAT id  -> id
+        T_LESSAND id  -> id
+        T_GREATAND id  -> id
+        T_LESSGREAT id  -> id
+        T_DLESSDASH id  -> id
+        T_CLOBBER id  -> id
+        T_If id  -> id
+        T_Then id  -> id
+        T_Else id  -> id
+        T_Elif id  -> id
+        T_Fi id  -> id
+        T_Do id  -> id
+        T_Done id  -> id
+        T_Case id  -> id
+        T_Esac id  -> id
+        T_While id  -> id
+        T_Until id  -> id
+        T_For id  -> id
+        T_Select id  -> id
+        T_Lbrace id  -> id
+        T_Rbrace id  -> id
+        T_Lparen id  -> id
+        T_Rparen id  -> id
+        T_Bang id  -> id
+        T_In  id  -> id
+        T_NEWLINE id  -> id
+        T_EOF id  -> id
+        T_Less id  -> id
+        T_Greater id  -> id
+        T_SingleQuoted id _  -> id
+        T_Literal id _  -> id
+        T_NormalWord id _  -> id
+        T_DoubleQuoted id _  -> id
+        T_DollarExpansion id _  -> id
+        T_DollarBraced id _  -> id
+        T_DollarArithmetic id _  -> id
+        T_BraceExpansion id _  -> id
+        T_ParamSubSpecialChar id _ -> id
+        T_DollarBraceCommandExpansion id _  -> id
+        T_IoFile id _ _  -> id
+        T_IoDuplicate id _ _  -> id
+        T_HereDoc id _ _ _ _ -> id
+        T_HereString id _  -> id
+        T_FdRedirect id _ _  -> id
+        T_Assignment id _ _ _ _  -> id
+        T_Array id _  -> id
+        T_IndexedElement id _ _  -> id
+        T_Redirecting id _ _  -> id
+        T_SimpleCommand id _ _  -> id
+        T_Pipeline id _ _  -> id
+        T_Banged id _  -> id
+        T_AndIf id _ _ -> id
+        T_OrIf id _ _ -> id
+        T_Backgrounded id _  -> id
+        T_IfExpression id _ _  -> id
+        T_Subshell id _  -> id
+        T_BraceGroup id _  -> id
+        T_WhileExpression id _ _  -> id
+        T_UntilExpression id _ _  -> id
+        T_ForIn id _ _ _  -> id
+        T_SelectIn id _ _ _  -> id
+        T_CaseExpression id _ _ -> id
+        T_Function id _ _ _ _  -> id
+        T_Arithmetic id _  -> id
+        T_Script id _ _  -> id
+        T_Condition id _ _  -> id
+        T_Extglob id _ _ -> id
+        T_Backticked id _ -> id
+        TC_And id _ _ _ _  -> id
+        TC_Or id _ _ _ _  -> id
+        TC_Group id _ _  -> id
+        TC_Binary id _ _ _ _  -> id
+        TC_Unary id _ _ _  -> id
+        TC_Nullary id _ _  -> id
+        TA_Binary id _ _ _  -> id
+        TA_Assignment id _ _ _  -> id
+        TA_Unary id _ _  -> id
+        TA_Sequence id _  -> id
+        TA_Trinary id _ _ _  -> id
+        TA_Expansion id _  -> id
+        T_ProcSub id _ _ -> id
+        T_Glob id _ -> id
+        T_ForArithmetic id _ _ _ _ -> id
+        T_DollarSingleQuoted id _ -> id
+        T_DollarDoubleQuoted id _ -> id
+        T_DollarBracket id _ -> id
+        T_Annotation id _ _ -> id
+        T_Pipe id _ -> id
+        T_CoProc id _ _ -> id
+        T_CoProcBody id _ -> id
+        T_Include id _ -> id
+        T_SourceCommand id _ _ -> id
+        T_UnparsedIndex id _ _ -> id
+        TC_Empty id _ -> id
+        TA_Variable id _ _ -> id
+
+blank :: Monad m => Token -> m ()
+blank = const $ return ()
+doAnalysis :: Monad m => (Token -> m ()) -> Token -> m Token
+doAnalysis f = analyze f blank return
+doStackAnalysis :: Monad m => (Token -> m ()) -> (Token -> m ()) -> Token -> m Token
+doStackAnalysis startToken endToken = analyze startToken endToken return
+doTransform :: (Token -> Token) -> Token -> Token
+doTransform i = runIdentity . analyze blank blank (return . i)
+

src/ShellCheck/ASTLib.hs

@@ -0,0 +1,492 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.ASTLib where
+
+import ShellCheck.AST
+
+import Control.Monad.Writer
+import Control.Monad
+import Data.Char
+import Data.Functor
+import Data.List
+import Data.Maybe
+
+-- Is this a type of loop?
+isLoop t = case t of
+        T_WhileExpression {} -> True
+        T_UntilExpression {} -> True
+        T_ForIn {} -> True
+        T_ForArithmetic {} -> True
+        T_SelectIn {}  -> True
+        _ -> False
+
+-- Will this split into multiple words when used as an argument?
+willSplit x =
+  case x of
+    T_DollarBraced {} -> True
+    T_DollarExpansion {} -> True
+    T_Backticked {} -> True
+    T_BraceExpansion {} -> True
+    T_Glob {} -> True
+    T_Extglob {} -> True
+    T_NormalWord _ l -> any willSplit l
+    _ -> False
+
+isGlob T_Extglob {} = True
+isGlob T_Glob {} = True
+isGlob (T_NormalWord _ l) = any isGlob l
+isGlob _ = False
+
+-- Is this shell word a constant?
+isConstant token =
+    case token of
+        -- This ignores some cases like ~"foo":
+        T_NormalWord _ (T_Literal _ ('~':_) : _)  -> False
+        T_NormalWord _ l   -> all isConstant l
+        T_DoubleQuoted _ l -> all isConstant l
+        T_SingleQuoted _ _ -> True
+        T_Literal _ _ -> True
+        _ -> False
+
+-- Is this an empty literal?
+isEmpty token =
+    case token of
+        T_NormalWord _ l   -> all isEmpty l
+        T_DoubleQuoted _ l -> all isEmpty l
+        T_SingleQuoted _ "" -> True
+        T_Literal _ "" -> True
+        _ -> False
+
+-- Quick&lazy oversimplification of commands, throwing away details
+-- and returning a list like  ["find", ".", "-name", "${VAR}*" ].
+oversimplify token =
+    case token of
+        (T_NormalWord _ l) -> [concat (concatMap oversimplify l)]
+        (T_DoubleQuoted _ l) -> [concat (concatMap oversimplify l)]
+        (T_SingleQuoted _ s) -> [s]
+        (T_DollarBraced _ _) -> ["${VAR}"]
+        (T_DollarArithmetic _ _) -> ["${VAR}"]
+        (T_DollarExpansion _ _) -> ["${VAR}"]
+        (T_Backticked _ _) -> ["${VAR}"]
+        (T_Glob _ s) -> [s]
+        (T_Pipeline _ _ [x]) -> oversimplify x
+        (T_Literal _ x) -> [x]
+        (T_ParamSubSpecialChar _ x) -> [x]
+        (T_SimpleCommand _ vars words) -> concatMap oversimplify words
+        (T_Redirecting _ _ foo) -> oversimplify foo
+        (T_DollarSingleQuoted _ s) -> [s]
+        (T_Annotation _ _ s) -> oversimplify s
+        -- Workaround for let "foo = bar" parsing
+        (TA_Sequence _ [TA_Expansion _ v]) -> concatMap oversimplify v
+        _ -> []
+
+
+-- Turn a SimpleCommand foo -avz --bar=baz into args "a", "v", "z", "bar",
+-- each in a tuple of (token, stringFlag). Non-flag arguments are added with
+-- stringFlag == "".
+getFlagsUntil stopCondition (T_SimpleCommand _ _ (_:args)) =
+    let tokenAndText = map (\x -> (x, concat $ oversimplify x)) args
+        (flagArgs, rest) = break (stopCondition . snd) tokenAndText
+    in
+        concatMap flag flagArgs ++ map (\(t, _) -> (t, "")) rest
+  where
+    flag (x, '-':'-':arg) = [ (x, takeWhile (/= '=') arg) ]
+    flag (x, '-':args) = map (\v -> (x, [v])) args
+    flag (x, _) = [ (x, "") ]
+getFlagsUntil _ _ = error "Internal shellcheck error, please report! (getFlags on non-command)"
+
+-- Get all flags in a GNU way, up until --
+getAllFlags :: Token -> [(Token, String)]
+getAllFlags = getFlagsUntil (== "--")
+-- Get all flags in a BSD way, up until first non-flag argument or --
+getLeadingFlags = getFlagsUntil (\x -> x == "--" || (not $ "-" `isPrefixOf` x))
+
+-- Check if a command has a flag.
+hasFlag cmd str = str `elem` (map snd $ getAllFlags cmd)
+
+-- Is this token a word that starts with a dash?
+isFlag token =
+    case getWordParts token of
+        T_Literal _ ('-':_) : _ -> True
+        _ -> False
+
+-- Is this token a flag where the - is unquoted?
+isUnquotedFlag token = fromMaybe False $ do
+    str <- getLeadingUnquotedString token
+    return $ "-" `isPrefixOf` str
+
+-- Given a T_DollarBraced, return a simplified version of the string contents.
+bracedString (T_DollarBraced _ l) = concat $ oversimplify l
+bracedString _ = error "Internal shellcheck error, please report! (bracedString on non-variable)"
+
+-- Is this an expansion of multiple items of an array?
+isArrayExpansion t@(T_DollarBraced _ _) =
+    let string = bracedString t in
+        "@" `isPrefixOf` string ||
+            not ("#" `isPrefixOf` string) && "[@]" `isInfixOf` string
+isArrayExpansion _ = False
+
+-- Is it possible that this arg becomes multiple args?
+mayBecomeMultipleArgs t = willBecomeMultipleArgs t || f t
+  where
+    f t@(T_DollarBraced _ _) =
+        let string = bracedString t in
+            "!" `isPrefixOf` string
+    f (T_DoubleQuoted _ parts) = any f parts
+    f (T_NormalWord _ parts) = any f parts
+    f _ = False
+
+-- Is it certain that this word will becomes multiple words?
+willBecomeMultipleArgs t = willConcatInAssignment t || f t
+  where
+    f T_Extglob {} = True
+    f T_Glob {} = True
+    f T_BraceExpansion {} = True
+    f (T_DoubleQuoted _ parts) = any f parts
+    f (T_NormalWord _ parts) = any f parts
+    f _ = False
+
+-- This does token cause implicit concatenation in assignments?
+willConcatInAssignment token =
+    case token of
+        t@T_DollarBraced {} -> isArrayExpansion t
+        (T_DoubleQuoted _ parts) -> any willConcatInAssignment parts
+        (T_NormalWord _ parts) -> any willConcatInAssignment parts
+        _ -> False
+
+-- Maybe get the literal string corresponding to this token
+getLiteralString :: Token -> Maybe String
+getLiteralString = getLiteralStringExt (const Nothing)
+
+-- Definitely get a literal string, skipping over all non-literals
+onlyLiteralString :: Token -> String
+onlyLiteralString = fromJust . getLiteralStringExt (const $ return "")
+
+-- Maybe get a literal string, but only if it's an unquoted argument.
+getUnquotedLiteral (T_NormalWord _ list) =
+    concat <$> mapM str list
+  where
+    str (T_Literal _ s) = return s
+    str _ = Nothing
+getUnquotedLiteral _ = Nothing
+
+-- Get the last unquoted T_Literal in a word like "${var}foo"THIS
+-- or nothing if the word does not end in an unquoted literal.
+getTrailingUnquotedLiteral :: Token -> Maybe Token
+getTrailingUnquotedLiteral t =
+    case t of
+        (T_NormalWord _ list@(_:_)) ->
+            from (last list)
+        _ -> Nothing
+  where
+    from t =
+        case t of
+            T_Literal {} -> return t
+            _ -> Nothing
+
+-- Get the leading, unquoted, literal string of a token (if any).
+getLeadingUnquotedString :: Token -> Maybe String
+getLeadingUnquotedString t =
+    case t of
+        T_NormalWord _ ((T_Literal _ s) : _) -> return s
+        _ -> Nothing
+
+-- Maybe get the literal string of this token and any globs in it.
+getGlobOrLiteralString = getLiteralStringExt f
+  where
+    f (T_Glob _ str) = return str
+    f _ = Nothing
+
+-- Maybe get the literal value of a token, using a custom function
+-- to map unrecognized Tokens into strings.
+getLiteralStringExt :: (Token -> Maybe String) -> Token -> Maybe String
+getLiteralStringExt more = g
+  where
+    allInList = fmap concat . mapM g
+    g (T_DoubleQuoted _ l) = allInList l
+    g (T_DollarDoubleQuoted _ l) = allInList l
+    g (T_NormalWord _ l) = allInList l
+    g (TA_Expansion _ l) = allInList l
+    g (T_SingleQuoted _ s) = return s
+    g (T_Literal _ s) = return s
+    g (T_ParamSubSpecialChar _ s) = return s
+    g (T_DollarSingleQuoted _ s) = return $ decodeEscapes s
+    g x = more x
+
+    -- Bash style $'..' decoding
+    decodeEscapes ('\\':c:cs) =
+        case c of
+            'a' -> '\a' : rest
+            'b' -> '\b' : rest
+            'e' -> '\x1B' : rest
+            'f' -> '\f' : rest
+            'n' -> '\n' : rest
+            'r' -> '\r' : rest
+            't' -> '\t' : rest
+            'v' -> '\v' : rest
+            '\'' -> '\'' : rest
+            '"' -> '"' : rest
+            '\\' -> '\\' : rest
+            'x' ->
+                case cs of
+                    (x:y:more) ->
+                        if isHexDigit x && isHexDigit y
+                        then chr (16*(digitToInt x) + (digitToInt y)) : rest
+                        else '\\':c:rest
+            _ | isOctDigit c ->
+                let digits = take 3 $ takeWhile isOctDigit (c:cs)
+                    num = parseOct digits
+                in (if num < 256 then chr num else '?') : rest
+            _ -> '\\' : c : rest
+      where
+        rest = decodeEscapes cs
+        parseOct = f 0
+          where
+            f n "" = n
+            f n (c:rest) = f (n * 8 + digitToInt c) rest
+    decodeEscapes (c:cs) = c : decodeEscapes cs
+    decodeEscapes [] = []
+
+-- Is this token a string literal?
+isLiteral t = isJust $ getLiteralString t
+
+
+-- Turn a NormalWord like foo="bar $baz" into a series of constituent elements like [foo=,bar ,$baz]
+getWordParts (T_NormalWord _ l)   = concatMap getWordParts l
+getWordParts (T_DoubleQuoted _ l) = l
+-- TA_Expansion is basically T_NormalWord for arithmetic expressions
+getWordParts (TA_Expansion _ l)   = concatMap getWordParts l
+getWordParts other                = [other]
+
+-- Return a list of NormalWords that would result from brace expansion
+braceExpand (T_NormalWord id list) = take 1000 $ do
+    items <- mapM part list
+    return $ T_NormalWord id items
+  where
+    part (T_BraceExpansion id items) = do
+        item <- items
+        braceExpand item
+    part x = return x
+
+-- Maybe get a SimpleCommand from immediate wrappers like T_Redirections
+getCommand t =
+    case t of
+        T_Redirecting _ _ w -> getCommand w
+        T_SimpleCommand _ _ (w:_) -> return t
+        T_Annotation _ _ t -> getCommand t
+        _ -> Nothing
+
+-- Maybe get the command name string of a token representing a command
+getCommandName :: Token -> Maybe String
+getCommandName = fst . getCommandNameAndToken
+
+-- Get the command name token from a command, i.e.
+-- the token representing 'ls' in 'ls -la 2> foo'.
+-- If it can't be determined, return the original token.
+getCommandTokenOrThis = snd . getCommandNameAndToken
+
+getCommandNameAndToken :: Token -> (Maybe String, Token)
+getCommandNameAndToken t = fromMaybe (Nothing, t) $ do
+    (T_SimpleCommand _ _ (w:rest)) <- getCommand t
+    s <- getLiteralString w
+    if "busybox" `isSuffixOf` s || "builtin" == s
+        then
+            case rest of
+                (applet:_) -> return (getLiteralString applet, applet)
+                _ -> return (Just s, w)
+        else
+            return (Just s, w)
+
+
+-- If a command substitution is a single command, get its name.
+--  $(date +%s) = Just "date"
+getCommandNameFromExpansion :: Token -> Maybe String
+getCommandNameFromExpansion t =
+    case t of
+        T_DollarExpansion _ [c] -> extract c
+        T_Backticked _ [c] -> extract c
+        T_DollarBraceCommandExpansion _ [c] -> extract c
+        _ -> Nothing
+  where
+    extract (T_Pipeline _ _ [cmd]) = getCommandName cmd
+    extract _ = Nothing
+
+-- Get the basename of a token representing a command
+getCommandBasename = fmap basename . getCommandName
+  where
+    basename = reverse . takeWhile (/= '/') . reverse
+
+isAssignment t =
+    case t of
+        T_Redirecting _ _ w -> isAssignment w
+        T_SimpleCommand _ (w:_) [] -> True
+        T_Assignment {} -> True
+        T_Annotation _ _ w -> isAssignment w
+        _ -> False
+
+isOnlyRedirection t =
+    case t of
+        T_Pipeline _ _ [x] -> isOnlyRedirection x
+        T_Annotation _ _ w -> isOnlyRedirection w
+        T_Redirecting _ (_:_) c -> isOnlyRedirection c
+        T_SimpleCommand _ [] [] -> True
+        _ -> False
+
+isFunction t = case t of T_Function {} -> True; _ -> False
+
+isBraceExpansion t = case t of T_BraceExpansion {} -> True; _ -> False
+
+-- Get the lists of commands from tokens that contain them, such as
+-- the body of while loops or branches of if statements.
+getCommandSequences :: Token -> [[Token]]
+getCommandSequences t =
+    case t of
+        T_Script _ _ cmds -> [cmds]
+        T_BraceGroup _ cmds -> [cmds]
+        T_Subshell _ cmds -> [cmds]
+        T_WhileExpression _ _ cmds -> [cmds]
+        T_UntilExpression _ _ cmds -> [cmds]
+        T_ForIn _ _ _ cmds -> [cmds]
+        T_ForArithmetic _ _ _ _ cmds -> [cmds]
+        T_IfExpression _ thens elses -> map snd thens ++ [elses]
+        T_Annotation _ _ t -> getCommandSequences t
+        _ -> []
+
+-- Get a list of names of associative arrays
+getAssociativeArrays t =
+    nub . execWriter $ doAnalysis f t
+  where
+    f :: Token -> Writer [String] ()
+    f t@T_SimpleCommand {} = fromMaybe (return ()) $ do
+        name <- getCommandName t
+        let assocNames = ["declare","local","typeset"]
+        guard $ elem name assocNames
+        let flags = getAllFlags t
+        guard $ elem "A" $ map snd flags
+        let args = map fst . filter ((==) "" . snd) $ flags
+        let names = mapMaybe (getLiteralStringExt nameAssignments) args
+        return $ tell names
+    f _ = return ()
+
+    nameAssignments t =
+        case t of
+            T_Assignment _ _ name _ _ -> return name
+            _ -> Nothing
+
+-- A Pseudoglob is a wildcard pattern used for checking if a match can succeed.
+-- For example, [[ $(cmd).jpg == [a-z] ]] will give the patterns *.jpg and ?, which
+-- can be proven never to match.
+data PseudoGlob = PGAny | PGMany | PGChar Char
+    deriving (Eq, Show)
+
+-- Turn a word into a PG pattern, replacing all unknown/runtime values with
+-- PGMany.
+wordToPseudoGlob :: Token -> Maybe [PseudoGlob]
+wordToPseudoGlob word =
+    simplifyPseudoGlob . concat <$> mapM f (getWordParts word)
+  where
+    f x = case x of
+        T_Literal _ s -> return $ map PGChar s
+        T_SingleQuoted _ s -> return $ map PGChar s
+
+        T_DollarBraced {} -> return [PGMany]
+        T_DollarExpansion {} -> return [PGMany]
+        T_Backticked {} -> return [PGMany]
+
+        T_Glob _ "?" -> return [PGAny]
+        T_Glob _ ('[':_)  -> return [PGAny]
+        T_Glob {} -> return [PGMany]
+
+        T_Extglob {} -> return [PGMany]
+
+        _ -> return [PGMany]
+
+-- Turn a word into a PG pattern, but only if we can preserve
+-- exact semantics.
+wordToExactPseudoGlob :: Token -> Maybe [PseudoGlob]
+wordToExactPseudoGlob word =
+    simplifyPseudoGlob . concat <$> mapM f (getWordParts word)
+  where
+    f x = case x of
+        T_Literal _ s -> return $ map PGChar s
+        T_SingleQuoted _ s -> return $ map PGChar s
+        T_Glob _ "?" -> return [PGAny]
+        T_Glob _ "*" -> return [PGMany]
+        _ -> fail "Unknown token type"
+
+-- Reorder a PseudoGlob for more efficient matching, e.g.
+-- f?*?**g -> f??*g
+simplifyPseudoGlob :: [PseudoGlob] -> [PseudoGlob]
+simplifyPseudoGlob = f
+  where
+    f [] = []
+    f (x@(PGChar _) : rest ) = x : f rest
+    f list =
+        let (anys, rest) = span (\x -> x == PGMany || x == PGAny) list in
+            order anys ++ f rest
+
+    order s = let (any, many) = partition (== PGAny) s in
+        any ++ take 1 many
+
+-- Check whether the two patterns can ever overlap.
+pseudoGlobsCanOverlap :: [PseudoGlob] -> [PseudoGlob] -> Bool
+pseudoGlobsCanOverlap = matchable
+  where
+    matchable x@(xf:xs) y@(yf:ys) =
+        case (xf, yf) of
+            (PGMany, _) -> matchable x ys || matchable xs y
+            (_, PGMany) -> matchable x ys || matchable xs y
+            (PGAny, _) -> matchable xs ys
+            (_, PGAny) -> matchable xs ys
+            (_, _) -> xf == yf && matchable xs ys
+
+    matchable [] [] = True
+    matchable (PGMany : rest) [] = matchable rest []
+    matchable (_:_) [] = False
+    matchable [] r = matchable r []
+
+-- Check whether the first pattern always overlaps the second.
+pseudoGlobIsSuperSetof :: [PseudoGlob] -> [PseudoGlob] -> Bool
+pseudoGlobIsSuperSetof = matchable
+  where
+    matchable x@(xf:xs) y@(yf:ys) =
+        case (xf, yf) of
+            (PGMany, PGMany) -> matchable x ys
+            (PGMany, _) -> matchable x ys || matchable xs y
+            (_, PGMany) -> False
+            (PGAny, _) -> matchable xs ys
+            (_, PGAny) -> False
+            (_, _) -> xf == yf && matchable xs ys
+
+    matchable [] [] = True
+    matchable (PGMany : rest) [] = matchable rest []
+    matchable _ _ = False
+
+wordsCanBeEqual x y = fromMaybe True $
+    liftM2 pseudoGlobsCanOverlap (wordToPseudoGlob x) (wordToPseudoGlob y)
+
+-- Is this an expansion that can be quoted,
+-- e.g. $(foo) `foo` $foo (but not {foo,})?
+isQuoteableExpansion t = case t of
+    T_DollarExpansion {} -> True
+    T_DollarBraceCommandExpansion {} -> True
+    T_Backticked {} -> True
+    T_DollarBraced {} -> True
+    _ -> False

src/ShellCheck/Analyzer.hs

@@ -0,0 +1,45 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Analyzer (analyzeScript) where
+
+import ShellCheck.Analytics
+import ShellCheck.AnalyzerLib
+import ShellCheck.Interface
+import Data.List
+import Data.Monoid
+import qualified ShellCheck.Checks.Commands
+import qualified ShellCheck.Checks.ShellSupport
+
+
+-- TODO: Clean up the cruft this is layered on
+analyzeScript :: AnalysisSpec -> AnalysisResult
+analyzeScript spec = newAnalysisResult {
+    arComments =
+        filterByAnnotation spec params . nub $
+            runAnalytics spec
+            ++ runChecker params (checkers params)
+}
+  where
+    params = makeParameters spec
+
+checkers params = mconcat $ map ($ params) [
+    ShellCheck.Checks.Commands.checker,
+    ShellCheck.Checks.ShellSupport.checker
+    ]

src/ShellCheck/AnalyzerLib.hs

@@ -0,0 +1,903 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TemplateHaskell  #-}
+module ShellCheck.AnalyzerLib where
+import           ShellCheck.AST
+import           ShellCheck.ASTLib
+import           ShellCheck.Data
+import           ShellCheck.Interface
+import           ShellCheck.Parser
+import           ShellCheck.Regex
+
+import           Control.Arrow          (first)
+import           Control.Monad.Identity
+import           Control.Monad.RWS
+import           Control.Monad.State
+import           Control.Monad.Writer
+import           Data.Char
+import           Data.List
+import qualified Data.Map               as Map
+import           Data.Maybe
+import           Data.Semigroup
+
+import           Test.QuickCheck.All    (forAllProperties)
+import           Test.QuickCheck.Test   (maxSuccess, quickCheckWithResult, stdArgs)
+
+type Analysis = AnalyzerM ()
+type AnalyzerM a = RWS Parameters [TokenComment] Cache a
+nullCheck = const $ return ()
+
+
+data Checker = Checker {
+    perScript :: Root -> Analysis,
+    perToken  :: Token -> Analysis
+}
+
+runChecker :: Parameters -> Checker -> [TokenComment]
+runChecker params checker = notes
+    where
+        root = rootNode params
+        check = perScript checker `composeAnalyzers` (\(Root x) -> void $ doAnalysis (perToken checker) x)
+        notes = snd $ evalRWS (check $ Root root) params Cache
+
+instance Semigroup Checker where
+    (<>) x y = Checker {
+        perScript = perScript x `composeAnalyzers` perScript y,
+        perToken = perToken x `composeAnalyzers` perToken y
+        }
+
+instance Monoid Checker where
+    mempty = Checker {
+        perScript = nullCheck,
+        perToken = nullCheck
+        }
+    mappend = (Data.Semigroup.<>)
+
+composeAnalyzers :: (a -> Analysis) -> (a -> Analysis) -> a -> Analysis
+composeAnalyzers f g x = f x >> g x
+
+data Parameters = Parameters {
+    hasLastpipe        :: Bool,           -- Whether this script has the 'lastpipe' option set/default.
+    hasSetE            :: Bool,           -- Whether this script has 'set -e' anywhere.
+    variableFlow       :: [StackData],   -- A linear (bad) analysis of data flow
+    parentMap          :: Map.Map Id Token, -- A map from Id to parent Token
+    shellType          :: Shell,            -- The shell type, such as Bash or Ksh
+    shellTypeSpecified :: Bool,    -- True if shell type was forced via flags
+    rootNode           :: Token              -- The root node of the AST
+    }
+
+-- TODO: Cache results of common AST ops here
+data Cache = Cache {}
+
+data Scope = SubshellScope String | NoneScope deriving (Show, Eq)
+data StackData =
+    StackScope Scope
+    | StackScopeEnd
+    -- (Base expression, specific position, var name, assigned values)
+    | Assignment (Token, Token, String, DataType)
+    | Reference (Token, Token, String)
+  deriving (Show)
+
+data DataType = DataString DataSource | DataArray DataSource
+  deriving (Show)
+
+data DataSource =
+    SourceFrom [Token]
+    | SourceExternal
+    | SourceDeclaration
+    | SourceInteger
+    | SourceChecked
+  deriving (Show)
+
+data VariableState = Dead Token String | Alive deriving (Show)
+
+defaultSpec root = spec {
+    asShellType = Nothing,
+    asCheckSourced = False,
+    asExecutionMode = Executed
+} where spec = newAnalysisSpec root
+
+pScript s =
+  let
+    pSpec = newParseSpec {
+        psFilename = "script",
+        psScript = s
+    }
+  in prRoot . runIdentity $ parseScript (mockedSystemInterface []) pSpec
+
+-- For testing. If parsed, returns whether there are any comments
+producesComments :: Checker -> String -> Maybe Bool
+producesComments c s = do
+        root <- pScript s
+        let spec = defaultSpec root
+        let params = makeParameters spec
+        return . not . null $ runChecker params c
+
+makeComment :: Severity -> Id -> Code -> String -> TokenComment
+makeComment severity id code note =
+    newTokenComment {
+        tcId = id,
+        tcComment = newComment {
+            cSeverity = severity,
+            cCode = code,
+            cMessage = note
+        }
+    }
+
+addComment note = tell [note]
+
+warn :: MonadWriter [TokenComment] m => Id -> Code -> String -> m ()
+warn  id code str = addComment $ makeComment WarningC id code str
+err   id code str = addComment $ makeComment ErrorC id code str
+info  id code str = addComment $ makeComment InfoC id code str
+style id code str = addComment $ makeComment StyleC id code str
+
+makeParameters spec =
+    let params = Parameters {
+        rootNode = root,
+        shellType = fromMaybe (determineShell root) $ asShellType spec,
+        hasSetE = containsSetE root,
+        hasLastpipe =
+            case shellType params of
+                Bash -> containsLastpipe root
+                Dash -> False
+                Sh   -> False
+                Ksh  -> True,
+
+        shellTypeSpecified = isJust $ asShellType spec,
+        parentMap = getParentTree root,
+        variableFlow = getVariableFlow params root
+    } in params
+  where root = asScript spec
+
+
+-- Does this script mention 'set -e' anywhere?
+-- Used as a hack to disable certain warnings.
+containsSetE root = isNothing $ doAnalysis (guard . not . isSetE) root
+  where
+    isSetE t =
+        case t of
+            T_Script _ str _ -> str `matches` re
+            T_SimpleCommand {}  ->
+                t `isUnqualifiedCommand` "set" &&
+                    ("errexit" `elem` oversimplify t ||
+                        "e" `elem` map snd (getAllFlags t))
+            _ -> False
+    re = mkRegex "[[:space:]]-[^-]*e"
+
+-- Does this script mention 'shopt -s lastpipe' anywhere?
+-- Also used as a hack.
+containsLastpipe root =
+        isNothing $ doAnalysis (guard . not . isShoptLastPipe) root
+    where
+        isShoptLastPipe t =
+            case t of
+                T_SimpleCommand {}  ->
+                    t `isUnqualifiedCommand` "shopt" &&
+                        ("lastpipe" `elem` oversimplify t)
+                _ -> False
+
+
+prop_determineShell0 = determineShell (fromJust $ pScript "#!/bin/sh") == Sh
+prop_determineShell1 = determineShell (fromJust $ pScript "#!/usr/bin/env ksh") == Ksh
+prop_determineShell2 = determineShell (fromJust $ pScript "") == Bash
+prop_determineShell3 = determineShell (fromJust $ pScript "#!/bin/sh -e") == Sh
+prop_determineShell4 = determineShell (fromJust $ pScript
+    "#!/bin/ksh\n#shellcheck shell=sh\nfoo") == Sh
+prop_determineShell5 = determineShell (fromJust $ pScript
+    "#shellcheck shell=sh\nfoo") == Sh
+prop_determineShell6 = determineShell (fromJust $ pScript "#! /bin/sh") == Sh
+prop_determineShell7 = determineShell (fromJust $ pScript "#! /bin/ash") == Dash
+determineShell t = fromMaybe Bash $ do
+    shellString <- foldl mplus Nothing $ getCandidates t
+    shellForExecutable shellString
+  where
+    forAnnotation t =
+        case t of
+            (ShellOverride s) -> return s
+            _                 -> fail ""
+    getCandidates :: Token -> [Maybe String]
+    getCandidates t@T_Script {} = [Just $ fromShebang t]
+    getCandidates (T_Annotation _ annotations s) =
+        map forAnnotation annotations ++
+           [Just $ fromShebang s]
+    fromShebang (T_Script _ s t) = executableFromShebang s
+
+-- Given a string like "/bin/bash" or "/usr/bin/env dash",
+-- return the shell basename like "bash" or "dash"
+executableFromShebang :: String -> String
+executableFromShebang = shellFor
+  where
+    shellFor s | "/env " `isInfixOf` s = head (drop 1 (words s)++[""])
+    shellFor s | ' ' `elem` s = shellFor $ takeWhile (/= ' ') s
+    shellFor s = reverse . takeWhile (/= '/') . reverse $ s
+
+
+
+-- Given a root node, make a map from Id to parent Token.
+-- This is used to populate parentMap in Parameters
+getParentTree :: Token -> Map.Map Id Token
+getParentTree t =
+    snd . snd $ runState (doStackAnalysis pre post t) ([], Map.empty)
+  where
+    pre t = modify (first ((:) t))
+    post t = do
+        (x, map) <- get
+        case x of
+          _:rest -> case rest of []    -> put (rest, map)
+                                 (x:_) -> put (rest, Map.insert (getId t) x map)
+
+-- Given a root node, make a map from Id to Token
+getTokenMap :: Token -> Map.Map Id Token
+getTokenMap t =
+    execState (doAnalysis f t) Map.empty
+  where
+    f t = modify (Map.insert (getId t) t)
+
+
+-- Is this token in a quoting free context? (i.e. would variable expansion split)
+-- True:  Assignments, [[ .. ]], here docs, already in double quotes
+-- False: Regular words
+isStrictlyQuoteFree = isQuoteFreeNode True
+
+-- Like above, but also allow some cases where splitting may be desired.
+-- True:  Like above + for loops
+-- False: Like above
+isQuoteFree = isQuoteFreeNode False
+
+
+isQuoteFreeNode strict tree t =
+    (isQuoteFreeElement t == Just True) ||
+        head (mapMaybe isQuoteFreeContext (drop 1 $ getPath tree t) ++ [False])
+  where
+    -- Is this node self-quoting in itself?
+    isQuoteFreeElement t =
+        case t of
+            T_Assignment {} -> return True
+            T_FdRedirect {} -> return True
+            _               -> Nothing
+
+    -- Are any subnodes inherently self-quoting?
+    isQuoteFreeContext t =
+        case t of
+            TC_Nullary _ DoubleBracket _    -> return True
+            TC_Unary _ DoubleBracket _ _    -> return True
+            TC_Binary _ DoubleBracket _ _ _ -> return True
+            TA_Sequence {}                  -> return True
+            T_Arithmetic {}                 -> return True
+            T_Assignment {}                 -> return True
+            T_Redirecting {}                -> return False
+            T_DoubleQuoted _ _              -> return True
+            T_DollarDoubleQuoted _ _        -> return True
+            T_CaseExpression {}             -> return True
+            T_HereDoc {}                    -> return True
+            T_DollarBraced {}               -> return True
+            -- When non-strict, pragmatically assume it's desirable to split here
+            T_ForIn {}                      -> return (not strict)
+            T_SelectIn {}                   -> return (not strict)
+            _                               -> Nothing
+
+-- Check if a token is a parameter to a certain command by name:
+-- Example: isParamTo (parentMap params) "sed" t
+isParamTo :: Map.Map Id Token -> String -> Token -> Bool
+isParamTo tree cmd =
+    go
+  where
+    go x = case Map.lookup (getId x) tree of
+                Nothing     -> False
+                Just parent -> check parent
+    check t =
+        case t of
+            T_SingleQuoted _ _ -> go t
+            T_DoubleQuoted _ _ -> go t
+            T_NormalWord _ _   -> go t
+            T_SimpleCommand {} -> isCommand t cmd
+            T_Redirecting {}   -> isCommand t cmd
+            _                  -> False
+
+-- Get the parent command (T_Redirecting) of a Token, if any.
+getClosestCommand :: Map.Map Id Token -> Token -> Maybe Token
+getClosestCommand tree t =
+    findFirst findCommand $ getPath tree t
+  where
+    findCommand t =
+        case t of
+            T_Redirecting {} -> return True
+            T_Script {}      -> return False
+            _                -> Nothing
+
+-- Like above, if koala_man knew Haskell when starting this project.
+getClosestCommandM t = do
+    tree <- asks parentMap
+    return $ getClosestCommand tree t
+
+-- Is the token used as a command name (the first word in a T_SimpleCommand)?
+usedAsCommandName tree token = go (getId token) (tail $ getPath tree token)
+  where
+    go currentId (T_NormalWord id [word]:rest)
+        | currentId == getId word = go id rest
+    go currentId (T_DoubleQuoted id [word]:rest)
+        | currentId == getId word = go id rest
+    go currentId (T_SimpleCommand _ _ (word:_):_)
+        | currentId == getId word = True
+    go _ _ = False
+
+-- A list of the element and all its parents up to the root node.
+getPath tree t = t :
+    case Map.lookup (getId t) tree of
+        Nothing     -> []
+        Just parent -> getPath tree parent
+
+-- Version of the above taking the map from the current context
+-- Todo: give this the name "getPath"
+getPathM t = do
+    map <- asks parentMap
+    return $ getPath map t
+
+isParentOf tree parent child =
+    elem (getId parent) . map getId $ getPath tree child
+
+parents params = getPath (parentMap params)
+
+pathTo t = do
+    parents <- reader parentMap
+    return $ getPath parents t
+
+-- Find the first match in a list where the predicate is Just True.
+-- Stops if it's Just False and ignores Nothing.
+findFirst :: (a -> Maybe Bool) -> [a] -> Maybe a
+findFirst p l =
+    case l of
+        [] -> Nothing
+        (x:xs) ->
+            case p x of
+                Just True  -> return x
+                Just False -> Nothing
+                Nothing    -> findFirst p xs
+
+-- Check whether a word is entirely output from a single command
+tokenIsJustCommandOutput t = case t of
+    T_NormalWord id [T_DollarExpansion _ cmds] -> check cmds
+    T_NormalWord id [T_DoubleQuoted _ [T_DollarExpansion _ cmds]] -> check cmds
+    T_NormalWord id [T_Backticked _ cmds] -> check cmds
+    T_NormalWord id [T_DoubleQuoted _ [T_Backticked _ cmds]] -> check cmds
+    _ -> False
+  where
+    check [x] = not $ isOnlyRedirection x
+    check _   = False
+
+-- TODO: Replace this with a proper Control Flow Graph
+getVariableFlow params t =
+    let (_, stack) = runState (doStackAnalysis startScope endScope t) []
+    in reverse stack
+  where
+    startScope t =
+        let scopeType = leadType params t
+        in do
+            when (scopeType /= NoneScope) $ modify (StackScope scopeType:)
+            when (assignFirst t) $ setWritten t
+
+    endScope t =
+        let scopeType = leadType params t
+        in do
+            setRead t
+            unless (assignFirst t) $ setWritten t
+            when (scopeType /= NoneScope) $ modify (StackScopeEnd:)
+
+    assignFirst T_ForIn {}    = True
+    assignFirst T_SelectIn {} = True
+    assignFirst _             = False
+
+    setRead t =
+        let read    = getReferencedVariables (parentMap params) t
+        in mapM_ (\v -> modify (Reference v:)) read
+
+    setWritten t =
+        let written = getModifiedVariables t
+        in mapM_ (\v -> modify (Assignment v:)) written
+
+
+leadType params t =
+    case t of
+        T_DollarExpansion _ _  -> SubshellScope "$(..) expansion"
+        T_Backticked _ _  -> SubshellScope "`..` expansion"
+        T_Backgrounded _ _  -> SubshellScope "backgrounding &"
+        T_Subshell _ _  -> SubshellScope "(..) group"
+        T_CoProcBody _ _  -> SubshellScope "coproc"
+        T_Redirecting {}  ->
+            if fromMaybe False causesSubshell
+            then SubshellScope "pipeline"
+            else NoneScope
+        _ -> NoneScope
+  where
+    parentPipeline = do
+        parent <- Map.lookup (getId t) (parentMap params)
+        case parent of
+            T_Pipeline {} -> return parent
+            _             -> Nothing
+
+    causesSubshell = do
+        (T_Pipeline _ _ list) <- parentPipeline
+        if length list <= 1
+            then return False
+            else if not $ hasLastpipe params
+                then return True
+                else return . not $ (getId . head $ reverse list) == getId t
+
+getModifiedVariables t =
+    case t of
+        T_SimpleCommand _ vars [] ->
+            concatMap (\x -> case x of
+                                T_Assignment id _ name _ w  ->
+                                    [(x, x, name, dataTypeFrom DataString w)]
+                                _ -> []
+                      ) vars
+        c@T_SimpleCommand {} ->
+            getModifiedVariableCommand c
+
+        TA_Unary _ "++|" v@(TA_Variable _ name _)  ->
+            [(t, v, name, DataString $ SourceFrom [v])]
+        TA_Unary _ "|++" v@(TA_Variable _ name _)  ->
+            [(t, v, name, DataString $ SourceFrom [v])]
+        TA_Assignment _ op (TA_Variable _ name _) rhs -> maybeToList $ do
+            guard $ op `elem` ["=", "*=", "/=", "%=", "+=", "-=", "<<=", ">>=", "&=", "^=", "|="]
+            return (t, t, name, DataString $ SourceFrom [rhs])
+
+        -- Count [[ -v foo ]] as an "assignment".
+        -- This is to prevent [ -v foo ] being unassigned or unused.
+        TC_Unary id _ "-v" token -> maybeToList $ do
+            str <- fmap (takeWhile (/= '[')) $ -- Quoted index
+                    flip getLiteralStringExt token $ \x ->
+                case x of
+                    T_Glob _ s -> return s -- Unquoted index
+                    _          -> Nothing
+
+            guard . not . null $ str
+            return (t, token, str, DataString SourceChecked)
+
+        T_DollarBraced _ l -> maybeToList $ do
+            let string = bracedString t
+            let modifier = getBracedModifier string
+            guard $ ":=" `isPrefixOf` modifier
+            return (t, t, getBracedReference string, DataString $ SourceFrom [l])
+
+        t@(T_FdRedirect _ ('{':var) op) -> -- {foo}>&2 modifies foo
+            [(t, t, takeWhile (/= '}') var, DataString SourceInteger) | not $ isClosingFileOp op]
+
+        t@(T_CoProc _ name _) ->
+            [(t, t, fromMaybe "COPROC" name, DataArray SourceInteger)]
+
+        --Points to 'for' rather than variable
+        T_ForIn id str [] _ -> [(t, t, str, DataString SourceExternal)]
+        T_ForIn id str words _ -> [(t, t, str, DataString $ SourceFrom words)]
+        T_SelectIn id str words _ -> [(t, t, str, DataString $ SourceFrom words)]
+        _ -> []
+
+isClosingFileOp op =
+    case op of
+        T_IoDuplicate _ (T_GREATAND _) "-" -> True
+        T_IoDuplicate _ (T_LESSAND  _) "-" -> True
+        _                                  -> False
+
+
+-- Consider 'export/declare -x' a reference, since it makes the var available
+getReferencedVariableCommand base@(T_SimpleCommand _ _ (T_NormalWord _ (T_Literal _ x:_):rest)) =
+    case x of
+        "export" -> if "f" `elem` flags
+            then []
+            else concatMap getReference rest
+        "declare" -> if
+                any (`elem` flags) ["x", "p"] &&
+                    (not $ any (`elem` flags) ["f", "F"])
+            then concatMap getReference rest
+            else []
+        "readonly" ->
+            if any (`elem` flags) ["f", "p"]
+            then []
+            else concatMap getReference rest
+        "trap" ->
+            case rest of
+                head:_ -> map (\x -> (head, head, x)) $ getVariablesFromLiteralToken head
+                _ -> []
+        _ -> []
+  where
+    getReference t@(T_Assignment _ _ name _ value) = [(t, t, name)]
+    getReference t@(T_NormalWord _ [T_Literal _ name]) | not ("-" `isPrefixOf` name) = [(t, t, name)]
+    getReference _ = []
+    flags = map snd $ getAllFlags base
+
+getReferencedVariableCommand _ = []
+
+-- The function returns a tuple consisting of four items describing an assignment.
+-- Given e.g. declare foo=bar
+-- (
+--   BaseCommand :: Token,     -- The command/structure assigning the variable, i.e. declare foo=bar
+--   AssignmentToken :: Token, -- The specific part that assigns this variable, i.e. foo=bar
+--   VariableName :: String,   -- The variable name, i.e. foo
+--   VariableValue :: DataType -- A description of the value being assigned, i.e. "Literal string with value foo"
+-- )
+getModifiedVariableCommand base@(T_SimpleCommand _ _ (T_NormalWord _ (T_Literal _ x:_):rest)) =
+   filter (\(_,_,s,_) -> not ("-" `isPrefixOf` s)) $
+    case x of
+        "read" ->
+            let params = map getLiteral rest
+                readArrayVars = getReadArrayVariables rest
+            in
+                catMaybes . (++ readArrayVars) . takeWhile isJust . reverse $ params
+        "getopts" ->
+            case rest of
+                opts:var:_ -> maybeToList $ getLiteral var
+                _          -> []
+
+        "let" -> concatMap letParamToLiteral rest
+
+        "export" ->
+            if "f" `elem` flags then [] else concatMap getModifierParamString rest
+
+        "declare" -> if any (`elem` flags) ["F", "f", "p"] then [] else declaredVars
+        "typeset" -> declaredVars
+
+        "local" -> concatMap getModifierParamString rest
+        "readonly" ->
+            if any (`elem` flags) ["f", "p"]
+            then []
+            else concatMap getModifierParamString rest
+        "set" -> maybeToList $ do
+            params <- getSetParams rest
+            return (base, base, "@", DataString $ SourceFrom params)
+
+        "printf" -> maybeToList $ getPrintfVariable rest
+
+        "mapfile" -> maybeToList $ getMapfileArray base rest
+        "readarray" -> maybeToList $ getMapfileArray base rest
+
+        _ -> []
+  where
+    flags = map snd $ getAllFlags base
+    stripEquals s = let rest = dropWhile (/= '=') s in
+        if rest == "" then "" else tail rest
+    stripEqualsFrom (T_NormalWord id1 (T_Literal id2 s:rs)) =
+        T_NormalWord id1 (T_Literal id2 (stripEquals s):rs)
+    stripEqualsFrom (T_NormalWord id1 [T_DoubleQuoted id2 [T_Literal id3 s]]) =
+        T_NormalWord id1 [T_DoubleQuoted id2 [T_Literal id3 (stripEquals s)]]
+    stripEqualsFrom t = t
+
+    declaredVars = concatMap (getModifierParam defaultType) rest
+      where
+        defaultType = if any (`elem` flags) ["a", "A"] then DataArray else DataString
+
+    getLiteralOfDataType t d = do
+        s <- getLiteralString t
+        when ("-" `isPrefixOf` s) $ fail "argument"
+        return (base, t, s, d)
+
+    getLiteral t = getLiteralOfDataType t (DataString SourceExternal)
+
+    getLiteralArray t = getLiteralOfDataType t (DataArray SourceExternal)
+
+    getModifierParamString = getModifierParam DataString
+
+    getModifierParam def t@(T_Assignment _ _ name _ value) =
+        [(base, t, name, dataTypeFrom def value)]
+    getModifierParam def t@T_NormalWord {} = maybeToList $ do
+        name <- getLiteralString t
+        guard $ isVariableName name
+        return (base, t, name, def SourceDeclaration)
+    getModifierParam _ _ = []
+
+    letParamToLiteral token =
+          if var == ""
+            then []
+            else [(base, token, var, DataString $ SourceFrom [stripEqualsFrom token])]
+        where var = takeWhile isVariableChar $ dropWhile (`elem` "+-") $ concat $ oversimplify token
+
+    getSetParams (t:_:rest) | getLiteralString t == Just "-o" = getSetParams rest
+    getSetParams (t:rest) =
+        let s = getLiteralString t in
+            case s of
+                Just "--"    -> return rest
+                Just ('-':_) -> getSetParams rest
+                _            -> return (t:fromMaybe [] (getSetParams rest))
+    getSetParams [] = Nothing
+
+    getPrintfVariable list = f $ map (\x -> (x, getLiteralString x)) list
+      where
+        f ((_, Just "-v") : (t, Just var) : _) = return (base, t, var, DataString $ SourceFrom list)
+        f (_:rest) = f rest
+        f [] = fail "not found"
+
+    -- mapfile has some curious syntax allowing flags plus 0..n variable names
+    -- where only the first non-option one is used if any. Here we cheat and
+    -- just get the last one, if it's a variable name.
+    getMapfileArray base arguments = do
+        lastArg <- listToMaybe (reverse arguments)
+        name <- getLiteralString lastArg
+        guard $ isVariableName name
+        return (base, lastArg, name, DataArray SourceExternal)
+
+    -- get all the array variables used in read, e.g. read -a arr
+    getReadArrayVariables args = do
+        map (getLiteralArray . snd)
+            (filter (\(x,_) -> getLiteralString x == Just "-a") (zip (args) (tail args)))
+
+getModifiedVariableCommand _ = []
+
+getIndexReferences s = fromMaybe [] $ do
+    match <- matchRegex re s
+    index <- match !!! 0
+    return $ matchAllStrings variableNameRegex index
+  where
+    re = mkRegex "(\\[.*\\])"
+
+prop_getOffsetReferences1 = getOffsetReferences ":bar" == ["bar"]
+prop_getOffsetReferences2 = getOffsetReferences ":bar:baz" == ["bar", "baz"]
+prop_getOffsetReferences3 = getOffsetReferences "[foo]:bar" == ["bar"]
+prop_getOffsetReferences4 = getOffsetReferences "[foo]:bar:baz" == ["bar", "baz"]
+getOffsetReferences mods = fromMaybe [] $ do
+-- if mods start with [, then drop until ]
+    match <- matchRegex re mods
+    offsets <- match !!! 1
+    return $ matchAllStrings variableNameRegex offsets
+  where
+    re = mkRegex "^(\\[.+\\])? *:([^-=?+].*)"
+
+getReferencedVariables parents t =
+    case t of
+        T_DollarBraced id l -> let str = bracedString t in
+            (t, t, getBracedReference str) :
+                map (\x -> (l, l, x)) (
+                    getIndexReferences str
+                    ++ getOffsetReferences (getBracedModifier str))
+        TA_Variable id name _ ->
+            if isArithmeticAssignment t
+            then []
+            else [(t, t, name)]
+        T_Assignment id mode str _ word ->
+            [(t, t, str) | mode == Append] ++ specialReferences str t word
+
+        TC_Unary id _ "-v" token -> getIfReference t token
+        TC_Unary id _ "-R" token -> getIfReference t token
+        TC_Binary id DoubleBracket op lhs rhs ->
+            if isDereferencing op
+            then concatMap (getIfReference t) [lhs, rhs]
+            else []
+
+        t@(T_FdRedirect _ ('{':var) op) -> -- {foo}>&- references and closes foo
+            [(t, t, takeWhile (/= '}') var) | isClosingFileOp op]
+        x -> getReferencedVariableCommand x
+  where
+    -- Try to reduce false positives for unused vars only referenced from evaluated vars
+    specialReferences name base word =
+        if name `elem` [
+            "PS1", "PS2", "PS3", "PS4",
+            "PROMPT_COMMAND"
+          ]
+        then
+            map (\x -> (base, base, x)) $
+                getVariablesFromLiteralToken word
+        else []
+
+    literalizer t = case t of
+        T_Glob _ s -> return s    -- Also when parsed as globs
+        _          -> Nothing
+
+    getIfReference context token = maybeToList $ do
+            str <- getLiteralStringExt literalizer token
+            guard . not $ null str
+            when (isDigit $ head str) $ fail "is a number"
+            return (context, token, getBracedReference str)
+
+    isDereferencing = (`elem` ["-eq", "-ne", "-lt", "-le", "-gt", "-ge"])
+
+    isArithmeticAssignment t = case getPath parents t of
+        this: TA_Assignment _ "=" lhs _ :_ -> lhs == t
+        _                                  -> False
+
+dataTypeFrom defaultType v = (case v of T_Array {} -> DataArray; _ -> defaultType) $ SourceFrom [v]
+
+
+--- Command specific checks
+
+-- Compare a command to a string: t `isCommand` "sed" (also matches /usr/bin/sed)
+isCommand token str = isCommandMatch token (\cmd -> cmd  == str || ('/' : str) `isSuffixOf` cmd)
+
+-- Compare a command to a literal. Like above, but checks full path.
+isUnqualifiedCommand token str = isCommandMatch token (== str)
+
+isCommandMatch token matcher = fromMaybe False $
+    fmap matcher (getCommandName token)
+
+-- Does this regex look like it was intended as a glob?
+-- True:  *foo*
+-- False: .*foo.*
+isConfusedGlobRegex :: String -> Bool
+isConfusedGlobRegex ('*':_) = True
+isConfusedGlobRegex [x,'*'] | x /= '\\' = True
+isConfusedGlobRegex _       = False
+
+isVariableStartChar x = x == '_' || isAsciiLower x || isAsciiUpper x
+isVariableChar x = isVariableStartChar x || isDigit x
+variableNameRegex = mkRegex "[_a-zA-Z][_a-zA-Z0-9]*"
+
+prop_isVariableName1 = isVariableName "_fo123"
+prop_isVariableName2 = not $ isVariableName "4"
+prop_isVariableName3 = not $ isVariableName "test: "
+isVariableName (x:r) = isVariableStartChar x && all isVariableChar r
+isVariableName _     = False
+
+getVariablesFromLiteralToken token =
+    getVariablesFromLiteral (fromJust $ getLiteralStringExt (const $ return " ") token)
+
+-- Try to get referenced variables from a literal string like "$foo"
+-- Ignores tons of cases like arithmetic evaluation and array indices.
+prop_getVariablesFromLiteral1 =
+    getVariablesFromLiteral "$foo${bar//a/b}$BAZ" == ["foo", "bar", "BAZ"]
+getVariablesFromLiteral string =
+    map (!! 0) $ matchAllSubgroups variableRegex string
+  where
+    variableRegex = mkRegex "\\$\\{?([A-Za-z0-9_]+)"
+
+-- Get the variable name from an expansion like ${var:-foo}
+prop_getBracedReference1 = getBracedReference "foo" == "foo"
+prop_getBracedReference2 = getBracedReference "#foo" == "foo"
+prop_getBracedReference3 = getBracedReference "#" == "#"
+prop_getBracedReference4 = getBracedReference "##" == "#"
+prop_getBracedReference5 = getBracedReference "#!" == "!"
+prop_getBracedReference6 = getBracedReference "!#" == "#"
+prop_getBracedReference7 = getBracedReference "!foo#?" == "foo"
+prop_getBracedReference8 = getBracedReference "foo-bar" == "foo"
+prop_getBracedReference9 = getBracedReference "foo:-bar" == "foo"
+prop_getBracedReference10= getBracedReference "foo: -1" == "foo"
+prop_getBracedReference11= getBracedReference "!os*" == ""
+prop_getBracedReference12= getBracedReference "!os?bar**" == ""
+prop_getBracedReference13= getBracedReference "foo[bar]" == "foo"
+getBracedReference s = fromMaybe s $
+    nameExpansion s `mplus` takeName noPrefix `mplus` getSpecial noPrefix `mplus` getSpecial s
+  where
+    noPrefix = dropPrefix s
+    dropPrefix (c:rest) = if c `elem` "!#" then rest else c:rest
+    dropPrefix ""       = ""
+    takeName s = do
+        let name = takeWhile isVariableChar s
+        guard . not $ null name
+        return name
+    getSpecial (c:_) =
+        if c `elem` "*@#?-$!" then return [c] else fail "not special"
+    getSpecial _ = fail "empty"
+
+    nameExpansion ('!':rest) = do -- e.g. ${!foo*bar*}
+        let suffix = dropWhile isVariableChar rest
+        guard $ suffix /= rest -- e.g. ${!@}
+        first <- suffix !!! 0
+        guard $ first `elem` "*?"
+        return ""
+    nameExpansion _ = Nothing
+
+prop_getBracedModifier1 = getBracedModifier "foo:bar:baz" == ":bar:baz"
+prop_getBracedModifier2 = getBracedModifier "!var:-foo" == ":-foo"
+prop_getBracedModifier3 = getBracedModifier "foo[bar]" == "[bar]"
+getBracedModifier s = fromMaybe "" . listToMaybe $ do
+    let var = getBracedReference s
+    a <- dropModifier s
+    dropPrefix var a
+  where
+    dropPrefix [] t        = return t
+    dropPrefix (a:b) (c:d) | a == c = dropPrefix b d
+    dropPrefix _ _         = []
+
+    dropModifier (c:rest) | c `elem` "#!" = [rest, c:rest]
+    dropModifier x        = [x]
+
+-- Useful generic functions.
+
+-- Run an action in a Maybe (or do nothing).
+-- Example:
+-- potentially $ do
+--   s <- getLiteralString cmd
+--   guard $ s `elem` ["--recursive", "-r"]
+--   return $ warn .. "Something something recursive"
+potentially :: Monad m => Maybe (m ()) -> m ()
+potentially = fromMaybe (return ())
+
+-- Get element 0 or a default. Like `head` but safe.
+headOrDefault _ (a:_) = a
+headOrDefault def _   = def
+
+--- Get element n of a list, or Nothing. Like `!!` but safe.
+(!!!) list i =
+    case drop i list of
+        []    -> Nothing
+        (r:_) -> Just r
+
+-- Run a command if the shell is in the given list
+whenShell l c = do
+    shell <- asks shellType
+    when (shell `elem` l ) c
+
+
+filterByAnnotation asSpec params =
+    filter (not . shouldIgnore)
+  where
+    token = asScript asSpec
+    shouldIgnore note =
+        any (shouldIgnoreFor (getCode note)) $
+            getPath parents (T_Bang $ tcId note)
+    shouldIgnoreFor num (T_Annotation _ anns _) =
+        any hasNum anns
+      where
+        hasNum (DisableComment ts) = num == ts
+        hasNum _                   = False
+    shouldIgnoreFor _ T_Include {} = not $ asCheckSourced asSpec
+    shouldIgnoreFor _ _ = False
+    parents = parentMap params
+    getCode = cCode . tcComment
+
+-- Is this a ${#anything}, to get string length or array count?
+isCountingReference (T_DollarBraced id token) =
+    case concat $ oversimplify token of
+        '#':_ -> True
+        _     -> False
+isCountingReference _ = False
+
+-- FIXME: doesn't handle ${a:+$var} vs ${a:+"$var"}
+isQuotedAlternativeReference t =
+    case t of
+        T_DollarBraced _ _ ->
+            getBracedModifier (bracedString t) `matches` re
+        _ -> False
+  where
+    re = mkRegex "(^|\\]):?\\+"
+
+-- getGnuOpts "erd:u:" will parse a SimpleCommand like
+--     read -re -d : -u 3 bar
+-- into
+--     Just [("r", -re), ("e", -re), ("d", :), ("u", 3), ("", bar)]
+-- where flags with arguments map to arguments, while others map to themselves.
+-- Any unrecognized flag will result in Nothing.
+getGnuOpts = getOpts getAllFlags
+getBsdOpts = getOpts getLeadingFlags
+getOpts :: (Token -> [(Token, String)]) -> String -> Token -> Maybe [(String, Token)]
+getOpts flagTokenizer string cmd = process flags
+  where
+    flags = flagTokenizer cmd
+    flagList (c:':':rest) = ([c], True) : flagList rest
+    flagList (c:rest)     = ([c], False) : flagList rest
+    flagList []           = []
+    flagMap = Map.fromList $ ("", False) : flagList string
+
+    process [] = return []
+    process [(token, flag)] = do
+        takesArg <- Map.lookup flag flagMap
+        guard $ not takesArg
+        return [(flag, token)]
+    process ((token1, flag1):rest2@((token2, flag2):rest)) = do
+        takesArg <- Map.lookup flag1 flagMap
+        if takesArg
+            then do
+                guard $ flag2 == ""
+                more <- process rest
+                return $ (flag1, token2) : more
+            else do
+                more <- process rest2
+                return $ (flag1, token1) : more
+
+return []
+runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])

src/ShellCheck/Checker.hs

@@ -0,0 +1,232 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE TemplateHaskell #-}
+module ShellCheck.Checker (checkScript, ShellCheck.Checker.runTests) where
+
+import ShellCheck.Interface
+import ShellCheck.Parser
+import ShellCheck.Analyzer
+
+import Data.Either
+import Data.Functor
+import Data.List
+import Data.Maybe
+import Data.Ord
+import Control.Monad.Identity
+import qualified Data.Map as Map
+import qualified System.IO
+import Prelude hiding (readFile)
+import Control.Monad
+
+import Test.QuickCheck.All
+
+tokenToPosition startMap t = fromMaybe fail $ do
+    span <- Map.lookup (tcId t) startMap
+    return $ newPositionedComment {
+        pcStartPos = fst span,
+        pcEndPos = snd span,
+        pcComment = tcComment t
+    }
+  where
+    fail = error "Internal shellcheck error: id doesn't exist. Please report!"
+
+checkScript :: Monad m => SystemInterface m -> CheckSpec -> m CheckResult
+checkScript sys spec = do
+    results <- checkScript (csScript spec)
+    return emptyCheckResult {
+        crFilename = csFilename spec,
+        crComments = results
+    }
+  where
+    checkScript contents = do
+        result <- parseScript sys newParseSpec {
+            psFilename = csFilename spec,
+            psScript = contents,
+            psCheckSourced = csCheckSourced spec,
+            psShellTypeOverride = csShellTypeOverride spec
+        }
+        let parseMessages = prComments result
+        let analysisMessages =
+                fromMaybe [] $
+                    (arComments . analyzeScript . analysisSpec)
+                        <$> prRoot result
+        let translator = tokenToPosition (prTokenPositions result)
+        return . nub . sortMessages . filter shouldInclude $
+            (parseMessages ++ map translator analysisMessages)
+
+    shouldInclude pc =
+        let code     = cCode (pcComment pc)
+            severity = cSeverity (pcComment pc)
+        in
+            code `notElem` csExcludedWarnings spec &&
+            severity <= csMinSeverity spec
+
+    sortMessages = sortBy (comparing order)
+    order pc =
+        let pos = pcStartPos pc
+            comment = pcComment pc in
+        (posFile pos,
+         posLine pos,
+         posColumn pos,
+         cSeverity comment,
+         cCode comment,
+         cMessage comment)
+    getPosition = pcStartPos
+
+    analysisSpec root =
+        as {
+            asScript = root,
+            asShellType = csShellTypeOverride spec,
+            asCheckSourced = csCheckSourced spec,
+            asExecutionMode = Executed
+         } where as = newAnalysisSpec root
+
+getErrors sys spec =
+    sort . map getCode . crComments $
+        runIdentity (checkScript sys spec)
+  where
+    getCode = cCode . pcComment
+
+check = checkWithIncludes []
+
+checkWithSpec includes =
+    getErrors (mockedSystemInterface includes)
+
+checkWithIncludes includes src =
+    checkWithSpec includes emptyCheckSpec {
+        csScript = src,
+        csExcludedWarnings = [2148]
+    }
+
+checkRecursive includes src =
+    checkWithSpec includes emptyCheckSpec {
+        csScript = src,
+        csExcludedWarnings = [2148],
+        csCheckSourced = True
+    }
+
+prop_findsParseIssue = check "echo \"$12\"" == [1037]
+
+prop_commentDisablesParseIssue1 =
+    null $ check "#shellcheck disable=SC1037\necho \"$12\""
+prop_commentDisablesParseIssue2 =
+    null $ check "#shellcheck disable=SC1037\n#lol\necho \"$12\""
+
+prop_findsAnalysisIssue =
+    check "echo $1" == [2086]
+prop_commentDisablesAnalysisIssue1 =
+    null $ check "#shellcheck disable=SC2086\necho $1"
+prop_commentDisablesAnalysisIssue2 =
+    null $ check "#shellcheck disable=SC2086\n#lol\necho $1"
+
+prop_optionDisablesIssue1 =
+    null $ getErrors
+                (mockedSystemInterface [])
+                emptyCheckSpec {
+                    csScript = "echo $1",
+                    csExcludedWarnings = [2148, 2086]
+                }
+
+prop_optionDisablesIssue2 =
+    null $ getErrors
+                (mockedSystemInterface [])
+                emptyCheckSpec {
+                    csScript = "echo \"$10\"",
+                    csExcludedWarnings = [2148, 1037]
+                }
+
+prop_wontParseBadShell =
+    [1071] == check "#!/usr/bin/python\ntrue $1\n"
+
+prop_optionDisablesBadShebang =
+    null $ getErrors
+                (mockedSystemInterface [])
+                emptyCheckSpec {
+                    csScript = "#!/usr/bin/python\ntrue\n",
+                    csShellTypeOverride = Just Sh
+                }
+
+prop_annotationDisablesBadShebang =
+    [] == check "#!/usr/bin/python\n# shellcheck shell=sh\ntrue\n"
+
+
+prop_canParseDevNull =
+    [] == check "source /dev/null"
+
+prop_failsWhenNotSourcing =
+    [1091, 2154] == check "source lol; echo \"$bar\""
+
+prop_worksWhenSourcing =
+    null $ checkWithIncludes [("lib", "bar=1")] "source lib; echo \"$bar\""
+
+prop_worksWhenDotting =
+    null $ checkWithIncludes [("lib", "bar=1")] ". lib; echo \"$bar\""
+
+prop_noInfiniteSourcing =
+    [] == checkWithIncludes  [("lib", "source lib")] "source lib"
+
+prop_canSourceBadSyntax =
+    [1094, 2086] == checkWithIncludes [("lib", "for f; do")] "source lib; echo $1"
+
+prop_cantSourceDynamic =
+    [1090] == checkWithIncludes [("lib", "")] ". \"$1\""
+
+prop_cantSourceDynamic2 =
+    [1090] == checkWithIncludes [("lib", "")] "source ~/foo"
+
+prop_canSourceDynamicWhenRedirected =
+    null $ checkWithIncludes [("lib", "")] "#shellcheck source=lib\n. \"$1\""
+
+prop_recursiveAnalysis =
+    [2086] == checkRecursive [("lib", "echo $1")] "source lib"
+
+prop_recursiveParsing =
+    [1037] == checkRecursive [("lib", "echo \"$10\"")] "source lib"
+
+prop_sourceDirectiveDoesntFollowFile =
+    null $ checkWithIncludes
+                [("foo", "source bar"), ("bar", "baz=3")]
+                "#shellcheck source=foo\n. \"$1\"; echo \"$baz\""
+
+prop_filewideAnnotationBase = [2086] == check "#!/bin/sh\necho $1"
+prop_filewideAnnotation1 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\necho $1"
+prop_filewideAnnotation2 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation3 = null $
+    check "#!/bin/sh\n#unrelated\n# shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation4 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\n#unrelated\ntrue\necho $1"
+prop_filewideAnnotation5 = null $
+    check "#!/bin/sh\n\n\n\n#shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation6 = null $
+    check "#shellcheck shell=sh\n#unrelated\n#shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation7 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\n#unrelated\ntrue\necho $1"
+
+prop_filewideAnnotationBase2 = [2086, 2181] == check "true\n[ $? == 0 ] && echo $1"
+prop_filewideAnnotation8 = null $
+    check "# Disable $? warning\n#shellcheck disable=SC2181\n# Disable quoting warning\n#shellcheck disable=2086\ntrue\n[ $? == 0 ] && echo $1"
+
+prop_sourcePartOfOriginalScript = -- #1181: -x disabled posix warning for 'source'
+    2039 `elem` checkWithIncludes [("./saywhat.sh", "echo foo")] "#!/bin/sh\nsource ./saywhat.sh"
+
+return []
+runTests = $quickCheckAll

src/ShellCheck/Checks/ShellSupport.hs

@@ -0,0 +1,423 @@
+{-
+    Copyright 2012-2016 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE FlexibleContexts #-}
+module ShellCheck.Checks.ShellSupport (checker , ShellCheck.Checks.ShellSupport.runTests) where
+
+import ShellCheck.AST
+import ShellCheck.ASTLib
+import ShellCheck.AnalyzerLib
+import ShellCheck.Interface
+import ShellCheck.Regex
+
+import Control.Monad
+import Control.Monad.RWS
+import Data.Char
+import Data.List
+import Data.Maybe
+import qualified Data.Map as Map
+import Test.QuickCheck.All (forAllProperties)
+import Test.QuickCheck.Test (quickCheckWithResult, stdArgs, maxSuccess)
+
+data ForShell = ForShell [Shell] (Token -> Analysis)
+
+getChecker params list = Checker {
+        perScript = nullCheck,
+        perToken = foldl composeAnalyzers nullCheck $ mapMaybe include list
+    }
+  where
+    shell = shellType params
+    include (ForShell list a) = do
+        guard $ shell `elem` list
+        return a
+
+checker params = getChecker params checks
+
+checks = [
+    checkForDecimals
+    ,checkBashisms
+    ,checkEchoSed
+    ,checkBraceExpansionVars
+    ,checkMultiDimensionalArrays
+    ,checkPS1Assignments
+    ]
+
+testChecker (ForShell _ t) =
+    Checker {
+        perScript = nullCheck,
+        perToken = t
+    }
+verify c s = producesComments (testChecker c) s == Just True
+verifyNot c s = producesComments (testChecker c) s == Just False
+
+prop_checkForDecimals1 = verify checkForDecimals "((3.14*c))"
+prop_checkForDecimals2 = verify checkForDecimals "foo[1.2]=bar"
+prop_checkForDecimals3 = verifyNot checkForDecimals "declare -A foo; foo[1.2]=bar"
+checkForDecimals = ForShell [Sh, Dash, Bash] f
+  where
+    f t@(TA_Expansion id _) = potentially $ do
+        str <- getLiteralString t
+        first <- str !!! 0
+        guard $ isDigit first && '.' `elem` str
+        return $ err id 2079 "(( )) doesn't support decimals. Use bc or awk."
+    f _ = return ()
+
+
+prop_checkBashisms = verify checkBashisms "while read a; do :; done < <(a)"
+prop_checkBashisms2 = verify checkBashisms "[ foo -nt bar ]"
+prop_checkBashisms3 = verify checkBashisms "echo $((i++))"
+prop_checkBashisms4 = verify checkBashisms "rm !(*.hs)"
+prop_checkBashisms5 = verify checkBashisms "source file"
+prop_checkBashisms6 = verify checkBashisms "[ \"$a\" == 42 ]"
+prop_checkBashisms7 = verify checkBashisms "echo ${var[1]}"
+prop_checkBashisms8 = verify checkBashisms "echo ${!var[@]}"
+prop_checkBashisms9 = verify checkBashisms "echo ${!var*}"
+prop_checkBashisms10= verify checkBashisms "echo ${var:4:12}"
+prop_checkBashisms11= verifyNot checkBashisms "echo ${var:-4}"
+prop_checkBashisms12= verify checkBashisms "echo ${var//foo/bar}"
+prop_checkBashisms13= verify checkBashisms "exec -c env"
+prop_checkBashisms14= verify checkBashisms "echo -n \"Foo: \""
+prop_checkBashisms15= verify checkBashisms "let n++"
+prop_checkBashisms16= verify checkBashisms "echo $RANDOM"
+prop_checkBashisms17= verify checkBashisms "echo $((RANDOM%6+1))"
+prop_checkBashisms18= verify checkBashisms "foo &> /dev/null"
+prop_checkBashisms19= verify checkBashisms "foo > file*.txt"
+prop_checkBashisms20= verify checkBashisms "read -ra foo"
+prop_checkBashisms21= verify checkBashisms "[ -a foo ]"
+prop_checkBashisms22= verifyNot checkBashisms "[ foo -a bar ]"
+prop_checkBashisms23= verify checkBashisms "trap mything ERR INT"
+prop_checkBashisms24= verifyNot checkBashisms "trap mything INT TERM"
+prop_checkBashisms25= verify checkBashisms "cat < /dev/tcp/host/123"
+prop_checkBashisms26= verify checkBashisms "trap mything ERR SIGTERM"
+prop_checkBashisms27= verify checkBashisms "echo *[^0-9]*"
+prop_checkBashisms28= verify checkBashisms "exec {n}>&2"
+prop_checkBashisms29= verify checkBashisms "echo ${!var}"
+prop_checkBashisms30= verify checkBashisms "printf -v '%s' \"$1\""
+prop_checkBashisms31= verify checkBashisms "printf '%q' \"$1\""
+prop_checkBashisms32= verifyNot checkBashisms "#!/bin/dash\n[ foo -nt bar ]"
+prop_checkBashisms33= verify checkBashisms "#!/bin/sh\necho -n foo"
+prop_checkBashisms34= verifyNot checkBashisms "#!/bin/dash\necho -n foo"
+prop_checkBashisms35= verifyNot checkBashisms "#!/bin/dash\nlocal foo"
+prop_checkBashisms36= verifyNot checkBashisms "#!/bin/dash\nread -p foo -r bar"
+prop_checkBashisms37= verifyNot checkBashisms "HOSTNAME=foo; echo $HOSTNAME"
+prop_checkBashisms38= verify checkBashisms "RANDOM=9; echo $RANDOM"
+prop_checkBashisms39= verify checkBashisms "foo-bar() { true; }"
+prop_checkBashisms40= verify checkBashisms "echo $(<file)"
+prop_checkBashisms41= verify checkBashisms "echo `<file`"
+prop_checkBashisms42= verify checkBashisms "trap foo int"
+prop_checkBashisms43= verify checkBashisms "trap foo sigint"
+prop_checkBashisms44= verifyNot checkBashisms "#!/bin/dash\ntrap foo int"
+prop_checkBashisms45= verifyNot checkBashisms "#!/bin/dash\ntrap foo INT"
+prop_checkBashisms46= verify checkBashisms "#!/bin/dash\ntrap foo SIGINT"
+prop_checkBashisms47= verify checkBashisms "#!/bin/dash\necho foo 42>/dev/null"
+prop_checkBashisms48= verifyNot checkBashisms "#!/bin/sh\necho $LINENO"
+prop_checkBashisms49= verify checkBashisms "#!/bin/dash\necho $MACHTYPE"
+prop_checkBashisms50= verify checkBashisms "#!/bin/sh\ncmd >& file"
+prop_checkBashisms51= verifyNot checkBashisms "#!/bin/sh\ncmd 2>&1"
+prop_checkBashisms52= verifyNot checkBashisms "#!/bin/sh\ncmd >&2"
+prop_checkBashisms53= verifyNot checkBashisms "#!/bin/sh\nprintf -- -f\n"
+prop_checkBashisms54= verify checkBashisms "#!/bin/sh\nfoo+=bar"
+prop_checkBashisms55= verify checkBashisms "#!/bin/sh\necho ${@%foo}"
+prop_checkBashisms56= verifyNot checkBashisms "#!/bin/sh\necho ${##}"
+checkBashisms = ForShell [Sh, Dash] $ \t -> do
+    params <- ask
+    kludge params t
+ where
+  -- This code was copy-pasted from Analytics where params was a variable
+  kludge params = bashism
+   where
+    isDash = shellType params == Dash
+    warnMsg id s =
+        if isDash
+        then warn id 2169 $ "In dash, " ++ s ++ " not supported."
+        else warn id 2039 $ "In POSIX sh, " ++ s ++ " undefined."
+
+    bashism (T_ProcSub id _ _) = warnMsg id "process substitution is"
+    bashism (T_Extglob id _ _) = warnMsg id "extglob is"
+    bashism (T_DollarSingleQuoted id _) = warnMsg id "$'..' is"
+    bashism (T_DollarDoubleQuoted id _) = warnMsg id "$\"..\" is"
+    bashism (T_ForArithmetic id _ _ _ _) = warnMsg id "arithmetic for loops are"
+    bashism (T_Arithmetic id _) = warnMsg id "standalone ((..)) is"
+    bashism (T_DollarBracket id _) = warnMsg id "$[..] in place of $((..)) is"
+    bashism (T_SelectIn id _ _ _) = warnMsg id "select loops are"
+    bashism (T_BraceExpansion id _) = warnMsg id "brace expansion is"
+    bashism (T_Condition id DoubleBracket _) = warnMsg id "[[ ]] is"
+    bashism (T_HereString id _) = warnMsg id "here-strings are"
+    bashism (TC_Binary id SingleBracket op _ _)
+        | op `elem` [ "<", ">", "\\<", "\\>", "<=", ">=", "\\<=", "\\>="] =
+            unless isDash $ warnMsg id $ "lexicographical " ++ op ++ " is"
+    bashism (TC_Binary id SingleBracket op _ _)
+        | op `elem` [ "-nt", "-ef" ] =
+            unless isDash $ warnMsg id $ op ++ " is"
+    bashism (TC_Binary id SingleBracket "==" _ _) =
+            warnMsg id "== in place of = is"
+    bashism (TC_Binary id SingleBracket "=~" _ _) =
+            warnMsg id "=~ regex matching is"
+    bashism (TC_Unary id _ "-a" _) =
+            warnMsg id "unary -a in place of -e is"
+    bashism (TA_Unary id op _)
+        | op `elem` [ "|++", "|--", "++|", "--|"] =
+            warnMsg id $ filter (/= '|') op ++ " is"
+    bashism (TA_Binary id "**" _ _) = warnMsg id "exponentials are"
+    bashism (T_FdRedirect id "&" (T_IoFile _ (T_Greater _) _)) = warnMsg id "&> is"
+    bashism (T_FdRedirect id "" (T_IoFile _ (T_GREATAND _) _)) = warnMsg id ">& is"
+    bashism (T_FdRedirect id ('{':_) _) = warnMsg id "named file descriptors are"
+    bashism (T_FdRedirect id num _)
+        | all isDigit num && length num > 1 = warnMsg id "FDs outside 0-9 are"
+    bashism (T_Assignment id Append _ _ _) =
+        warnMsg id "+= is"
+    bashism (T_IoFile id _ word) | isNetworked =
+            warnMsg id "/dev/{tcp,udp} is"
+        where
+            file = onlyLiteralString word
+            isNetworked = any (`isPrefixOf` file) ["/dev/tcp", "/dev/udp"]
+    bashism (T_Glob id str) | "[^" `isInfixOf` str =
+            warnMsg id "^ in place of ! in glob bracket expressions is"
+
+    bashism t@(TA_Variable id str _) | isBashVariable str =
+        warnMsg id $ str ++ " is"
+
+    bashism t@(T_DollarBraced id token) = do
+        mapM_ check expansion
+        when (isBashVariable var) $
+                    warnMsg id $ var ++ " is"
+      where
+        str = bracedString t
+        var = getBracedReference str
+        check (regex, feature) =
+            when (isJust $ matchRegex regex str) $ warnMsg id feature
+
+    bashism t@(T_Pipe id "|&") =
+        warnMsg id "|& in place of 2>&1 | is"
+    bashism (T_Array id _) =
+        warnMsg id "arrays are"
+    bashism (T_IoFile id _ t) | isGlob t =
+        warnMsg id "redirecting to/from globs is"
+    bashism (T_CoProc id _ _) =
+        warnMsg id "coproc is"
+
+    bashism (T_Function id _ _ str _) | not (isVariableName str) =
+        warnMsg id "naming functions outside [a-zA-Z_][a-zA-Z0-9_]* is"
+
+    bashism (T_DollarExpansion id [x]) | isOnlyRedirection x =
+        warnMsg id "$(<file) to read files is"
+    bashism (T_Backticked id [x]) | isOnlyRedirection x =
+        warnMsg id "`<file` to read files is"
+
+    bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
+        | t `isCommand` "echo" && "-" `isPrefixOf` argString =
+            unless ("--" `isPrefixOf` argString) $ -- echo "-----"
+                if isDash
+                then
+                    when (argString /= "-n") $
+                        warnMsg (getId arg) "echo flags besides -n"
+                else
+                    warnMsg (getId arg) "echo flags are"
+      where argString = concat $ oversimplify arg
+    bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
+        | t `isCommand` "exec" && "-" `isPrefixOf` concat (oversimplify arg) =
+            warnMsg (getId arg) "exec flags are"
+    bashism t@(T_SimpleCommand id _ _)
+        | t `isCommand` "let" = warnMsg id "'let' is"
+
+    bashism t@(T_SimpleCommand id _ (cmd:rest)) =
+        let name = fromMaybe "" $ getCommandName t
+            flags = getLeadingFlags t
+        in do
+            when (name `elem` unsupportedCommands) $
+                warnMsg id $ "'" ++ name ++ "' is"
+            potentially $ do
+                allowed <- Map.lookup name allowedFlags
+                (word, flag) <- listToMaybe $
+                    filter (\x -> (not . null . snd $ x) && snd x `notElem` allowed) flags
+                return . warnMsg (getId word) $ name ++ " -" ++ flag ++ " is"
+
+            when (name == "source") $ warnMsg id "'source' in place of '.' is"
+            when (name == "trap") $
+                let
+                    check token = potentially $ do
+                        str <- getLiteralString token
+                        let upper = map toUpper str
+                        return $ do
+                            when (upper `elem` ["ERR", "DEBUG", "RETURN"]) $
+                                warnMsg (getId token) $ "trapping " ++ str ++ " is"
+                            when ("SIG" `isPrefixOf` upper) $
+                                warnMsg (getId token)
+                                    "prefixing signal names with 'SIG' is"
+                            when (not isDash && upper /= str) $
+                                warnMsg (getId token)
+                                    "using lower/mixed case for signal names is"
+                in
+                    mapM_ check (drop 1 rest)
+
+            when (name == "printf") $ potentially $ do
+                format <- rest !!! 0  -- flags are covered by allowedFlags
+                let literal = onlyLiteralString format
+                guard $ "%q" `isInfixOf` literal
+                return $ warnMsg (getId format) "printf %q is"
+      where
+        unsupportedCommands = [
+            "let", "caller", "builtin", "complete", "compgen", "declare", "dirs", "disown",
+            "enable", "mapfile", "readarray", "pushd", "popd", "shopt", "suspend",
+            "typeset"
+            ] ++ if not isDash then ["local"] else []
+        allowedFlags = Map.fromList [
+            ("exec", []),
+            ("export", ["-p"]),
+            ("printf", []),
+            ("read", if isDash then ["r", "p"] else ["r"]),
+            ("ulimit", ["f"])
+            ]
+    bashism t@(T_SourceCommand id src _) =
+        let name = fromMaybe "" $ getCommandName src
+        in do
+            when (name == "source") $ warnMsg id "'source' in place of '.' is"
+    bashism _ = return ()
+
+    varChars="_0-9a-zA-Z"
+    expansion = let re = mkRegex in [
+        (re $ "^![" ++ varChars ++ "]", "indirect expansion is"),
+        (re $ "^[" ++ varChars ++ "]+\\[.*\\]$", "array references are"),
+        (re $ "^![" ++ varChars ++ "]+\\[[*@]]$", "array key expansion is"),
+        (re $ "^![" ++ varChars ++ "]+[*@]$", "name matching prefixes are"),
+        (re $ "^[" ++ varChars ++ "*@]+:[^-=?+]", "string indexing is"),
+        (re $ "^([*@][%#]|#[@*])", "string operations on $@/$* are"),
+        (re $ "^[" ++ varChars ++ "*@]+(\\[.*\\])?/", "string replacement is")
+        ]
+    bashVars = [
+        "OSTYPE", "MACHTYPE", "HOSTTYPE", "HOSTNAME",
+        "DIRSTACK", "EUID", "UID", "SHLVL", "PIPESTATUS", "SHELLOPTS"
+        ]
+    bashDynamicVars = [ "RANDOM", "SECONDS" ]
+    dashVars = [ ]
+    isBashVariable var =
+        (var `elem` bashDynamicVars
+            || var `elem` bashVars && not (isAssigned var))
+        && not (isDash && var `elem` dashVars)
+    isAssigned var = any f (variableFlow params)
+      where
+        f x = case x of
+                Assignment (_, _, name, _) -> name == var
+                _ -> False
+
+prop_checkEchoSed1 = verify checkEchoSed "FOO=$(echo \"$cow\" | sed 's/foo/bar/g')"
+prop_checkEchoSed2 = verify checkEchoSed "rm $(echo $cow | sed -e 's,foo,bar,')"
+checkEchoSed = ForShell [Bash, Ksh] f
+  where
+    f (T_Pipeline id _ [a, b]) =
+        when (acmd == ["echo", "${VAR}"]) $
+            case bcmd of
+                ["sed", v] -> checkIn v
+                ["sed", "-e", v] -> checkIn v
+                _ -> return ()
+      where
+        -- This should have used backreferences, but TDFA doesn't support them
+        sedRe = mkRegex "^s(.)([^\n]*)g?$"
+        isSimpleSed s = fromMaybe False $ do
+            [first,rest] <- matchRegex sedRe s
+            let delimiters = filter (== head first) rest
+            guard $ length delimiters == 2
+            return True
+
+        acmd = oversimplify a
+        bcmd = oversimplify b
+        checkIn s =
+            when (isSimpleSed s) $
+                style id 2001 "See if you can use ${variable//search/replace} instead."
+    f _ = return ()
+
+
+prop_checkBraceExpansionVars1 = verify checkBraceExpansionVars "echo {1..$n}"
+prop_checkBraceExpansionVars2 = verifyNot checkBraceExpansionVars "echo {1,3,$n}"
+prop_checkBraceExpansionVars3 = verify checkBraceExpansionVars "eval echo DSC{0001..$n}.jpg"
+prop_checkBraceExpansionVars4 = verify checkBraceExpansionVars "echo {$i..100}"
+checkBraceExpansionVars = ForShell [Bash] f
+  where
+    f t@(T_BraceExpansion id list) = mapM_ check list
+      where
+        check element =
+            when (any (`isInfixOf` toString element) ["$..", "..$"]) $ do
+                c <- isEvaled element
+                if c
+                    then style id 2175 "Quote this invalid brace expansion since it should be passed literally to eval."
+                    else warn id 2051 "Bash doesn't support variables in brace range expansions."
+    f _ = return ()
+
+    literalExt t =
+        case t of
+            T_DollarBraced {} -> return "$"
+            T_DollarExpansion {} -> return "$"
+            T_DollarArithmetic {} -> return "$"
+            otherwise -> return "-"
+    toString t = fromJust $ getLiteralStringExt literalExt t
+    isEvaled t = do
+        cmd <- getClosestCommandM t
+        return $ isJust cmd && fromJust cmd `isUnqualifiedCommand` "eval"
+
+
+prop_checkMultiDimensionalArrays1 = verify checkMultiDimensionalArrays "foo[a][b]=3"
+prop_checkMultiDimensionalArrays2 = verifyNot checkMultiDimensionalArrays "foo[a]=3"
+prop_checkMultiDimensionalArrays3 = verify checkMultiDimensionalArrays "foo=( [a][b]=c )"
+prop_checkMultiDimensionalArrays4 = verifyNot checkMultiDimensionalArrays "foo=( [a]=c )"
+prop_checkMultiDimensionalArrays5 = verify checkMultiDimensionalArrays "echo ${foo[bar][baz]}"
+prop_checkMultiDimensionalArrays6 = verifyNot checkMultiDimensionalArrays "echo ${foo[bar]}"
+checkMultiDimensionalArrays = ForShell [Bash] f
+  where
+    f token =
+        case token of
+            T_Assignment _ _ name (first:second:_) _ -> about second
+            T_IndexedElement _ (first:second:_) _ -> about second
+            T_DollarBraced {} ->
+                when (isMultiDim token) $ about token
+            _ -> return ()
+    about t = warn (getId t) 2180 "Bash does not support multidimensional arrays. Use 1D or associative arrays."
+
+    re = mkRegex "^\\[.*\\]\\[.*\\]"  -- Fixme, this matches ${foo:- [][]} and such as well
+    isMultiDim t = getBracedModifier (bracedString t) `matches` re
+
+prop_checkPS11 = verify checkPS1Assignments "PS1='\\033[1;35m\\$ '"
+prop_checkPS11a= verify checkPS1Assignments "export PS1='\\033[1;35m\\$ '"
+prop_checkPSf2 = verify checkPS1Assignments "PS1='\\h \\e[0m\\$ '"
+prop_checkPS13 = verify checkPS1Assignments "PS1=$'\\x1b[c '"
+prop_checkPS14 = verify checkPS1Assignments "PS1=$'\\e[3m; '"
+prop_checkPS14a= verify checkPS1Assignments "export PS1=$'\\e[3m; '"
+prop_checkPS15 = verifyNot checkPS1Assignments "PS1='\\[\\033[1;35m\\]\\$ '"
+prop_checkPS16 = verifyNot checkPS1Assignments "PS1='\\[\\e1m\\e[1m\\]\\$ '"
+prop_checkPS17 = verifyNot checkPS1Assignments "PS1='e033x1B'"
+prop_checkPS18 = verifyNot checkPS1Assignments "PS1='\\[\\e\\]'"
+checkPS1Assignments = ForShell [Bash] f
+  where
+    f token = case token of
+        (T_Assignment _ _ "PS1" _ word) -> warnFor word
+        _ -> return ()
+
+    warnFor word =
+        let contents = concat $ oversimplify word in
+            when (containsUnescaped contents) $
+                info (getId word) 2025 "Make sure all escape sequences are enclosed in \\[..\\] to prevent line wrapping issues"
+    containsUnescaped s =
+        let unenclosed = subRegex enclosedRegex s "" in
+           isJust $ matchRegex escapeRegex unenclosed
+    enclosedRegex = mkRegex "\\\\\\[.*\\\\\\]" -- FIXME: shouldn't be eager
+    escapeRegex = mkRegex "\\\\x1[Bb]|\\\\e|\x1B|\\\\033"
+
+
+return []
+runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])

src/ShellCheck/Data.hs

@@ -0,0 +1,117 @@
+module ShellCheck.Data where
+
+import ShellCheck.Interface
+import Data.Version (showVersion)
+import Paths_ShellCheck (version)
+
+shellcheckVersion = showVersion version
+
+internalVariables = [
+    -- Generic
+    "", "_", "rest", "REST",
+
+    -- Bash
+    "BASH", "BASHOPTS", "BASHPID", "BASH_ALIASES", "BASH_ARGC",
+    "BASH_ARGV", "BASH_CMDS", "BASH_COMMAND", "BASH_EXECUTION_STRING",
+    "BASH_LINENO", "BASH_REMATCH", "BASH_SOURCE", "BASH_SUBSHELL",
+    "BASH_VERSINFO", "BASH_VERSION", "COMP_CWORD", "COMP_KEY",
+    "COMP_LINE", "COMP_POINT", "COMP_TYPE", "COMP_WORDBREAKS",
+    "COMP_WORDS", "COPROC", "DIRSTACK", "EUID", "FUNCNAME", "GROUPS",
+    "HISTCMD", "HOSTNAME", "HOSTTYPE", "LINENO", "MACHTYPE", "MAPFILE",
+    "OLDPWD", "OPTARG", "OPTIND", "OSTYPE", "PIPESTATUS", "PPID", "PWD",
+    "RANDOM", "READLINE_LINE", "READLINE_POINT", "REPLY", "SECONDS",
+    "SHELLOPTS", "SHLVL", "UID", "BASH_ENV", "BASH_XTRACEFD", "CDPATH",
+    "COLUMNS", "COMPREPLY", "EMACS", "ENV", "FCEDIT", "FIGNORE",
+    "FUNCNEST", "GLOBIGNORE", "HISTCONTROL", "HISTFILE", "HISTFILESIZE",
+    "HISTIGNORE", "HISTSIZE", "HISTTIMEFORMAT", "HOME", "HOSTFILE", "IFS",
+    "IGNOREEOF", "INPUTRC", "LANG", "LC_ALL", "LC_COLLATE", "LC_CTYPE",
+    "LC_MESSAGES", "LC_MONETARY", "LC_NUMERIC", "LC_TIME", "LINES", "MAIL",
+    "MAILCHECK", "MAILPATH", "OPTERR", "PATH", "POSIXLY_CORRECT",
+    "PROMPT_COMMAND", "PROMPT_DIRTRIM", "PS1", "PS2", "PS3", "PS4", "SHELL",
+    "TIMEFORMAT", "TMOUT", "TMPDIR", "auto_resume", "histchars", "COPROC",
+
+    -- Other
+    "USER", "TZ", "TERM", "LOGNAME", "LD_LIBRARY_PATH", "LANGUAGE", "DISPLAY",
+    "HOSTNAME", "KRB5CCNAME", "XAUTHORITY"
+
+    -- Ksh
+    , ".sh.version"
+  ]
+
+variablesWithoutSpaces = [
+    "$", "-", "?", "!", "#",
+    "BASHPID", "BASH_ARGC", "BASH_LINENO", "BASH_SUBSHELL", "EUID", "LINENO",
+    "OPTIND", "PPID", "RANDOM", "SECONDS", "SHELLOPTS", "SHLVL", "UID",
+    "COLUMNS", "HISTFILESIZE", "HISTSIZE", "LINES"
+  ]
+
+arrayVariables = [
+    "BASH_ALIASES", "BASH_ARGC", "BASH_ARGV", "BASH_CMDS", "BASH_LINENO",
+    "BASH_REMATCH", "BASH_SOURCE", "BASH_VERSINFO", "COMP_WORDS", "COPROC",
+    "DIRSTACK", "FUNCNAME", "GROUPS", "MAPFILE", "PIPESTATUS", "COMPREPLY"
+  ]
+
+commonCommands = [
+    "admin", "alias", "ar", "asa", "at", "awk", "basename", "batch",
+    "bc", "bg", "break", "c99", "cal", "cat", "cd", "cflow", "chgrp",
+    "chmod", "chown", "cksum", "cmp", "colon", "comm", "command",
+    "compress", "continue", "cp", "crontab", "csplit", "ctags", "cut",
+    "cxref", "date", "dd", "delta", "df", "diff", "dirname", "dot",
+    "du", "echo", "ed", "env", "eval", "ex", "exec", "exit", "expand",
+    "export", "expr", "fc", "fg", "file", "find", "fold", "fort77",
+    "fuser", "gencat", "get", "getconf", "getopts", "grep", "hash",
+    "head", "iconv", "ipcrm", "ipcs", "jobs", "join", "kill", "lex",
+    "link", "ln", "locale", "localedef", "logger", "logname", "lp",
+    "ls", "m4", "mailx", "make", "man", "mesg", "mkdir", "mkfifo",
+    "more", "mv", "newgrp", "nice", "nl", "nm", "nohup", "od", "paste",
+    "patch", "pathchk", "pax", "pr", "printf", "prs", "ps", "pwd",
+    "qalter", "qdel", "qhold", "qmove", "qmsg", "qrerun", "qrls",
+    "qselect", "qsig", "qstat", "qsub", "read", "readonly", "renice",
+    "return", "rm", "rmdel", "rmdir", "sact", "sccs", "sed", "set",
+    "sh", "shift", "sleep", "sort", "split", "strings", "strip", "stty",
+    "tabs", "tail", "talk", "tee", "test", "time", "times", "touch",
+    "tput", "tr", "trap", "tsort", "tty", "type", "ulimit", "umask",
+    "unalias", "uname", "uncompress", "unexpand", "unget", "uniq",
+    "unlink", "unset", "uucp", "uudecode", "uuencode", "uustat", "uux",
+    "val", "vi", "wait", "wc", "what", "who", "write", "xargs", "yacc",
+    "zcat"
+  ]
+
+nonReadingCommands = [
+    "alias", "basename", "bg", "cal", "cd", "chgrp", "chmod", "chown",
+    "cp", "du", "echo", "export", "false", "fg", "fuser", "getconf",
+    "getopt", "getopts", "ipcrm", "ipcs", "jobs", "kill", "ln", "ls",
+    "locale", "mv", "printf", "ps", "pwd", "renice", "rm", "rmdir",
+    "set", "sleep", "touch", "trap", "true", "ulimit", "unalias", "uname"
+    ]
+
+sampleWords = [
+    "alpha", "bravo", "charlie", "delta", "echo", "foxtrot",
+    "golf", "hotel", "india", "juliett", "kilo", "lima", "mike",
+    "november", "oscar", "papa", "quebec", "romeo", "sierra",
+    "tango", "uniform", "victor", "whiskey", "xray", "yankee",
+    "zulu"
+  ]
+
+binaryTestOps = [
+    "-nt", "-ot", "-ef", "==", "!=", "<=", ">=", "-eq", "-ne", "-lt", "-le",
+    "-gt", "-ge", "=~", ">", "<", "=", "\\<", "\\>", "\\<=", "\\>="
+  ]
+
+unaryTestOps = [
+    "!", "-a", "-b", "-c", "-d", "-e", "-f", "-g", "-h", "-L", "-k", "-p",
+    "-r", "-s", "-S", "-t", "-u", "-w", "-x", "-O", "-G", "-N", "-z", "-n",
+    "-o", "-v", "-R"
+  ]
+
+shellForExecutable :: String -> Maybe Shell
+shellForExecutable name =
+    case name of
+        "sh"    -> return Sh
+        "bash"  -> return Bash
+        "dash"  -> return Dash
+        "ash"   -> return Dash -- There's also a warning for this.
+        "ksh"   -> return Ksh
+        "ksh88" -> return Ksh
+        "ksh93" -> return Ksh
+        otherwise -> Nothing

src/ShellCheck/Formatter/CheckStyle.hs

@@ -0,0 +1,95 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.CheckStyle (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.Char
+import Data.List
+import GHC.Exts
+import System.IO
+
+format :: IO Formatter
+format = return Formatter {
+    header = do
+        putStrLn "<?xml version='1.0' encoding='UTF-8'?>"
+        putStrLn "<checkstyle version='4.3'>",
+
+    onFailure = outputError,
+    onResult = outputResults,
+
+    footer = putStrLn "</checkstyle>"
+}
+
+outputResults cr sys =
+    if null comments
+    then outputFile (crFilename cr) "" []
+    else mapM_ outputGroup fileGroups
+  where
+    comments = crComments cr
+    fileGroups = groupWith sourceFile comments
+    outputGroup group = do
+        let filename = sourceFile (head group)
+        result <- (siReadFile sys) filename
+        let contents = either (const "") id result
+        outputFile filename contents group
+
+outputFile filename contents warnings = do
+    let comments = makeNonVirtual warnings contents
+    putStrLn . formatFile filename $ comments
+
+formatFile name comments = concat [
+    "<file ", attr "name" name, ">\n",
+        concatMap formatComment comments,
+    "</file>"
+    ]
+
+formatComment c = concat [
+    "<error ",
+    attr "line" $ show . lineNo $ c,
+    attr "column" $ show . colNo $ c,
+    attr "severity" . severity $ severityText c,
+    attr "message" $ messageText c,
+    attr "source" $ "ShellCheck.SC" ++ show (codeNo c),
+    "/>\n"
+    ]
+
+outputError file error = putStrLn $ concat [
+    "<file ", attr "name" file, ">\n",
+    "<error ",
+        attr "line" "1",
+        attr "column" "1",
+        attr "severity" "error",
+        attr "message" error,
+        attr "source" "ShellCheck",
+    "/>\n",
+    "</file>"
+    ]
+
+
+attr s v = concat [ s, "='", escape v, "' " ]
+escape = concatMap escape'
+escape' c = if isOk c then [c] else "&#" ++ show (ord c) ++ ";"
+isOk x = any ($x) [isAsciiUpper, isAsciiLower, isDigit, (`elem` " ./")]
+
+severity "error" = "error"
+severity "warning" = "warning"
+severity _ = "info"

src/ShellCheck/Formatter/Format.hs

@@ -0,0 +1,70 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.Format where
+
+import ShellCheck.Data
+import ShellCheck.Interface
+
+-- A formatter that carries along an arbitrary piece of data
+data Formatter = Formatter {
+    header ::  IO (),
+    onResult :: CheckResult -> SystemInterface IO -> IO (),
+    onFailure :: FilePath -> ErrorMessage -> IO (),
+    footer :: IO ()
+}
+
+sourceFile = posFile . pcStartPos
+lineNo = posLine . pcStartPos
+endLineNo = posLine . pcEndPos
+colNo  = posColumn . pcStartPos
+endColNo = posColumn . pcEndPos
+codeNo = cCode . pcComment
+messageText = cMessage . pcComment
+
+severityText :: PositionedComment -> String
+severityText pc =
+    case cSeverity (pcComment pc) of
+        ErrorC   -> "error"
+        WarningC -> "warning"
+        InfoC    -> "info"
+        StyleC   -> "style"
+
+-- Realign comments from a tabstop of 8 to 1
+makeNonVirtual comments contents =
+    map fix comments
+  where
+    ls = lines contents
+    fix c = c {
+        pcStartPos = (pcStartPos c) {
+            posColumn = realignColumn lineNo colNo c
+        }
+      , pcEndPos = (pcEndPos c) {
+            posColumn = realignColumn endLineNo endColNo c
+        }
+    }
+    realignColumn lineNo colNo c =
+      if lineNo c > 0 && lineNo c <= fromIntegral (length ls)
+      then real (ls !! fromIntegral (lineNo c - 1)) 0 0 (colNo c)
+      else colNo c
+    real _ r v target | target <= v = r
+    real [] r v _ = r -- should never happen
+    real ('\t':rest) r v target =
+        real rest (r+1) (v + 8 - (v `mod` 8)) target
+    real (_:rest) r v target = real rest (r+1) (v+1) target

src/ShellCheck/Formatter/GCC.hs

@@ -0,0 +1,65 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.GCC (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.List
+import GHC.Exts
+import System.IO
+
+format :: IO Formatter
+format = return Formatter {
+    header = return (),
+    footer = return (),
+    onFailure = outputError,
+    onResult = outputAll
+}
+
+outputError file error = hPutStrLn stderr $ file ++ ": " ++ error
+
+outputAll cr sys = mapM_ f groups
+  where
+    comments = crComments cr
+    groups = groupWith sourceFile comments
+    f :: [PositionedComment] -> IO ()
+    f group = do
+        let filename = sourceFile (head group)
+        result <- (siReadFile sys) filename
+        let contents = either (const "") id result
+        outputResult filename contents group
+
+outputResult filename contents warnings = do
+    let comments = makeNonVirtual warnings contents
+    mapM_ (putStrLn . formatComment filename) comments
+
+formatComment filename c = concat [
+    filename, ":",
+    show $ lineNo c, ":",
+    show $ colNo c, ": ",
+    case severityText c of
+        "error" -> "error"
+        "warning" -> "warning"
+        _ -> "note",
+    ": ",
+    concat . lines $ messageText c,
+    " [SC", show $ codeNo c, "]"
+  ]

src/ShellCheck/Formatter/JSON.hs

@@ -0,0 +1,80 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.JSON (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.Aeson
+import Data.IORef
+import Data.Monoid
+import GHC.Exts
+import System.IO
+import qualified Data.ByteString.Lazy.Char8 as BL
+
+format = do
+    ref <- newIORef []
+    return Formatter {
+        header = return (),
+        onResult = collectResult ref,
+        onFailure = outputError,
+        footer = finish ref
+    }
+
+instance ToJSON (PositionedComment) where
+  toJSON comment =
+    let start = pcStartPos comment
+        end = pcEndPos comment
+        c = pcComment comment in
+    object [
+      "file" .= posFile start,
+      "line" .= posLine start,
+      "endLine" .= posLine end,
+      "column" .= posColumn start,
+      "endColumn" .= posColumn end,
+      "level" .= severityText comment,
+      "code" .= cCode c,
+      "message" .= cMessage c
+    ]
+
+  toEncoding comment =
+    let start = pcStartPos comment
+        end = pcEndPos comment
+        c = pcComment comment in
+    pairs (
+         "file" .= posFile start
+      <> "line" .= posLine start
+      <> "endLine" .= posLine end
+      <> "column" .= posColumn start
+      <> "endColumn" .= posColumn end
+      <> "level" .= severityText comment
+      <> "code" .= cCode c
+      <> "message" .= cMessage c
+    )
+
+outputError file msg = hPutStrLn stderr $ file ++ ": " ++ msg
+collectResult ref result _ =
+    modifyIORef ref (\x -> crComments result ++ x)
+
+finish ref = do
+    list <- readIORef ref
+    BL.putStrLn $ encode list
+

src/ShellCheck/Formatter/TTY.hs

@@ -0,0 +1,161 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.TTY (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Control.Monad
+import Data.IORef
+import Data.List
+import GHC.Exts
+import System.IO
+import System.Info
+
+wikiLink = "https://www.shellcheck.net/wiki/"
+
+-- An arbitrary Ord thing to order warnings
+type Ranking = (Char, Severity, Integer)
+
+format :: FormatterOptions -> IO Formatter
+format options = do
+    topErrorRef <- newIORef []
+    return Formatter {
+        header = return (),
+        footer = outputWiki topErrorRef,
+        onFailure = outputError options,
+        onResult = outputResult options topErrorRef
+    }
+
+colorForLevel level =
+    case level of
+        "error"   -> 31 -- red
+        "warning" -> 33 -- yellow
+        "info"    -> 32 -- green
+        "style"   -> 32 -- green
+        "message" -> 1 -- bold
+        "source"  -> 0 -- none
+        _ -> 0         -- none
+
+rankError :: PositionedComment -> Ranking
+rankError err = (ranking, cSeverity $ pcComment err, cCode $ pcComment err)
+  where
+    ranking =
+        if cCode (pcComment err) `elem` uninteresting
+        then 'Z'
+        else 'A'
+
+    -- A list of the most generic, least directly helpful
+    -- error codes to downrank.
+    uninteresting = [
+        1009, -- Mentioned parser error was..
+        1019, -- Expected this to be an argument
+        1036, -- ( is invalid here
+        1047, -- Expected 'fi'
+        1062, -- Expected 'done'
+        1070, -- Parsing stopped here (generic)
+        1072, -- Missing/unexpected ..
+        1073, -- Couldn't parse this ..
+        1088, -- Parsing stopped here (paren)
+        1089  -- Parsing stopped here (keyword)
+        ]
+
+appendComments errRef comments max = do
+    previous <- readIORef errRef
+    let current = map (\x -> (rankError x, cCode $ pcComment x, cMessage $ pcComment x)) comments
+    writeIORef errRef . take max . nubBy equal . sort $ previous ++ current
+  where
+    fst3 (x,_,_) = x
+    equal x y = fst3 x == fst3 y
+
+outputWiki :: IORef [(Ranking, Integer, String)] -> IO ()
+outputWiki errRef = do
+    issues <- readIORef errRef
+    unless (null issues) $ do
+        putStrLn "For more information:"
+        mapM_ showErr issues
+  where
+    showErr (_, code, msg) =
+        putStrLn $ "  " ++ wikiLink ++ "SC" ++ show code ++ " -- " ++ shorten msg
+    limit = 36
+    shorten msg =
+        if length msg < limit
+        then msg
+        else (take (limit-3) msg) ++ "..."
+
+outputError options file error = do
+    color <- getColorFunc $ foColorOption options
+    hPutStrLn stderr $ color "error" $ file ++ ": " ++ error
+
+outputResult options ref result sys = do
+    color <- getColorFunc $ foColorOption options
+    let comments = crComments result
+    appendComments ref comments (fromIntegral $ foWikiLinkCount options)
+    let fileGroups = groupWith sourceFile comments
+    mapM_ (outputForFile color sys) fileGroups
+
+outputForFile color sys comments = do
+    let fileName = sourceFile (head comments)
+    result <- (siReadFile sys) fileName
+    let contents = either (const "") id result
+    let fileLines = lines contents
+    let lineCount = fromIntegral $ length fileLines
+    let groups = groupWith lineNo comments
+    mapM_ (\x -> do
+        let lineNum = lineNo (head x)
+        let line = if lineNum < 1 || lineNum > lineCount
+                        then ""
+                        else fileLines !! fromIntegral (lineNum - 1)
+        putStrLn ""
+        putStrLn $ color "message" $
+           "In " ++ fileName ++" line " ++ show lineNum ++ ":"
+        putStrLn (color "source" line)
+        mapM_ (\c -> putStrLn (color (severityText c) $ cuteIndent c)) x
+        putStrLn ""
+      ) groups
+
+cuteIndent :: PositionedComment -> String
+cuteIndent comment =
+    replicate (fromIntegral $ colNo comment - 1) ' ' ++
+        makeArrow ++ " " ++ code (codeNo comment) ++ ": " ++ messageText comment
+  where
+    arrow n = '^' : replicate (fromIntegral $ n-2) '-' ++ "^"
+    makeArrow =
+        let sameLine = lineNo comment == endLineNo comment
+            delta = endColNo comment - colNo comment
+        in
+            if sameLine && delta > 2 && delta < 32 then arrow delta else "^--"
+
+code num = "SC" ++ show num
+
+getColorFunc colorOption = do
+    term <- hIsTerminalDevice stdout
+    let windows = "mingw" `isPrefixOf` os
+    let isUsableTty = term && not windows
+    let useColor = case colorOption of
+                       ColorAlways -> True
+                       ColorNever -> False
+                       ColorAuto -> isUsableTty
+    return $ if useColor then colorComment else const id
+  where
+    colorComment level comment =
+        ansi (colorForLevel level) ++ comment ++ clear
+    clear = ansi 0
+    ansi n = "\x1B[" ++ show n ++ "m"

src/ShellCheck/Interface.hs

@@ -0,0 +1,232 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Interface
+    (
+    SystemInterface(..)
+    , CheckSpec(csFilename, csScript, csCheckSourced, csExcludedWarnings, csShellTypeOverride, csMinSeverity)
+    , CheckResult(crFilename, crComments)
+    , ParseSpec(psFilename, psScript, psCheckSourced, psShellTypeOverride)
+    , ParseResult(prComments, prTokenPositions, prRoot)
+    , AnalysisSpec(asScript, asShellType, asExecutionMode, asCheckSourced)
+    , AnalysisResult(arComments)
+    , FormatterOptions(foColorOption, foWikiLinkCount)
+    , Shell(Ksh, Sh, Bash, Dash)
+    , ExecutionMode(Executed, Sourced)
+    , ErrorMessage
+    , Code
+    , Severity(ErrorC, WarningC, InfoC, StyleC)
+    , Position(posFile, posLine, posColumn)
+    , Comment(cSeverity, cCode, cMessage)
+    , PositionedComment(pcStartPos , pcEndPos , pcComment)
+    , ColorOption(ColorAuto, ColorAlways, ColorNever)
+    , TokenComment(tcId, tcComment)
+    , emptyCheckResult
+    , newParseResult
+    , newAnalysisSpec
+    , newAnalysisResult
+    , newFormatterOptions
+    , newPosition
+    , newTokenComment
+    , mockedSystemInterface
+    , newParseSpec
+    , emptyCheckSpec
+    , newPositionedComment
+    , newComment
+    ) where
+
+import ShellCheck.AST
+import Control.Monad.Identity
+import qualified Data.Map as Map
+
+
+newtype SystemInterface m = SystemInterface {
+    -- Read a file by filename, or return an error
+    siReadFile :: String -> m (Either ErrorMessage String)
+}
+
+-- ShellCheck input and output
+data CheckSpec = CheckSpec {
+    csFilename :: String,
+    csScript :: String,
+    csCheckSourced :: Bool,
+    csExcludedWarnings :: [Integer],
+    csShellTypeOverride :: Maybe Shell,
+    csMinSeverity :: Severity
+} deriving (Show, Eq)
+
+data CheckResult = CheckResult {
+    crFilename :: String,
+    crComments :: [PositionedComment]
+} deriving (Show, Eq)
+
+emptyCheckResult :: CheckResult
+emptyCheckResult = CheckResult {
+    crFilename = "",
+    crComments = []
+}
+
+emptyCheckSpec :: CheckSpec
+emptyCheckSpec = CheckSpec {
+    csFilename = "",
+    csScript = "",
+    csCheckSourced = False,
+    csExcludedWarnings = [],
+    csShellTypeOverride = Nothing,
+    csMinSeverity = StyleC
+}
+
+newParseSpec :: ParseSpec
+newParseSpec = ParseSpec {
+    psFilename = "",
+    psScript = "",
+    psCheckSourced = False,
+    psShellTypeOverride = Nothing
+}
+
+-- Parser input and output
+data ParseSpec = ParseSpec {
+    psFilename :: String,
+    psScript :: String,
+    psCheckSourced :: Bool,
+    psShellTypeOverride :: Maybe Shell
+} deriving (Show, Eq)
+
+data ParseResult = ParseResult {
+    prComments :: [PositionedComment],
+    prTokenPositions :: Map.Map Id (Position, Position),
+    prRoot :: Maybe Token
+} deriving (Show, Eq)
+
+newParseResult :: ParseResult
+newParseResult = ParseResult {
+    prComments = [],
+    prTokenPositions = Map.empty,
+    prRoot = Nothing
+}
+
+-- Analyzer input and output
+data AnalysisSpec = AnalysisSpec {
+    asScript :: Token,
+    asShellType :: Maybe Shell,
+    asExecutionMode :: ExecutionMode,
+    asCheckSourced :: Bool
+}
+
+newAnalysisSpec token = AnalysisSpec {
+    asScript = token,
+    asShellType = Nothing,
+    asExecutionMode = Executed,
+    asCheckSourced = False
+}
+
+newtype AnalysisResult = AnalysisResult {
+    arComments :: [TokenComment]
+}
+
+newAnalysisResult = AnalysisResult {
+    arComments = []
+}
+
+-- Formatter options
+data FormatterOptions = FormatterOptions {
+    foColorOption :: ColorOption,
+    foWikiLinkCount :: Integer
+}
+
+newFormatterOptions = FormatterOptions {
+    foColorOption = ColorAuto,
+    foWikiLinkCount = 3
+}
+
+
+-- Supporting data types
+data Shell = Ksh | Sh | Bash | Dash deriving (Show, Eq)
+data ExecutionMode = Executed | Sourced deriving (Show, Eq)
+
+type ErrorMessage = String
+type Code = Integer
+
+data Severity = ErrorC | WarningC | InfoC | StyleC deriving (Show, Eq, Ord)
+data Position = Position {
+    posFile :: String,    -- Filename
+    posLine :: Integer,   -- 1 based source line
+    posColumn :: Integer  -- 1 based source column, where tabs are 8
+} deriving (Show, Eq)
+
+newPosition :: Position
+newPosition = Position {
+    posFile   = "",
+    posLine   = 1,
+    posColumn = 1
+}
+
+data Comment = Comment {
+    cSeverity :: Severity,
+    cCode     :: Code,
+    cMessage  :: String
+} deriving (Show, Eq)
+
+newComment :: Comment
+newComment = Comment {
+    cSeverity = StyleC,
+    cCode     = 0,
+    cMessage  = ""
+}
+
+data PositionedComment = PositionedComment {
+    pcStartPos :: Position,
+    pcEndPos   :: Position,
+    pcComment  :: Comment
+} deriving (Show, Eq)
+
+newPositionedComment :: PositionedComment
+newPositionedComment = PositionedComment {
+    pcStartPos = newPosition,
+    pcEndPos   = newPosition,
+    pcComment  = newComment
+}
+
+data TokenComment = TokenComment {
+    tcId :: Id,
+    tcComment :: Comment
+} deriving (Show, Eq)
+
+newTokenComment = TokenComment {
+    tcId = Id 0,
+    tcComment = newComment
+}
+
+data ColorOption =
+    ColorAuto
+    | ColorAlways
+    | ColorNever
+  deriving (Ord, Eq, Show)
+
+-- For testing
+mockedSystemInterface :: [(String, String)] -> SystemInterface Identity
+mockedSystemInterface files = SystemInterface {
+    siReadFile = rf
+}
+  where
+    rf file =
+        case filter ((== file) . fst) files of
+            [] -> return $ Left "File not included in mock."
+            [(_, contents)] -> return $ Right contents
+

src/ShellCheck/Regex.hs

@@ -0,0 +1,80 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE FlexibleContexts #-}
+
+-- Basically Text.Regex based on regex-tdfa instead of the buggy regex-posix.
+module ShellCheck.Regex where
+
+import Data.List
+import Data.Maybe
+import Control.Monad
+import Text.Regex.TDFA
+
+-- Precompile the regex
+mkRegex :: String -> Regex
+mkRegex str =
+    let make :: RegexMaker Regex CompOption ExecOption String => String -> Regex
+        make = makeRegex
+    in
+        make str
+
+-- Does the regex match?
+matches :: String -> Regex -> Bool
+matches = flip match
+
+-- Get all subgroups of the first match
+matchRegex :: Regex -> String -> Maybe [String]
+matchRegex re str = do
+    (_, _, _, groups) <- matchM re str :: Maybe (String,String,String,[String])
+    return groups
+
+-- Get all full matches
+matchAllStrings :: Regex -> String -> [String]
+matchAllStrings re = unfoldr f
+  where
+    f :: String -> Maybe (String, String)
+    f str = do
+        (_, match, rest, _) <- matchM re str :: Maybe (String, String, String, [String])
+        return (match, rest)
+
+-- Get all subgroups from all matches
+matchAllSubgroups :: Regex -> String -> [[String]]
+matchAllSubgroups re = unfoldr f
+  where
+    f :: String -> Maybe ([String], String)
+    f str = do
+        (_, _, rest, groups) <- matchM re str :: Maybe (String, String, String, [String])
+        return (groups, rest)
+
+-- Replace regex in input with string
+subRegex :: Regex -> String -> String -> String
+subRegex re input replacement = f input
+  where
+    f str = fromMaybe str $ do
+        (before, match, after) <- matchM re str :: Maybe (String, String, String)
+        when (null match) $ error ("Internal error: substituted empty in " ++ str)
+        return $ before ++ replacement ++ f after
+
+-- Split a string based on a regex.
+splitOn :: String -> Regex -> [String]
+splitOn input re =
+    case matchM re input :: Maybe (String, String, String) of
+        Just (before, match, after) -> before : after `splitOn` re
+        Nothing -> [input]

stack.yaml

@@ -0,0 +1,35 @@
+# This file was automatically generated by stack init
+# For more information, see: https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
+resolver: lts-8.5
+
+# Local packages, usually specified by relative directory name
+packages:
+- '.'
+# Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
+extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: >= 1.0.0
+
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor

striptests

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# This file strips all unit tests from ShellCheck, removing
+# the dependency on QuickCheck and Template Haskell and
+# reduces the binary size considerably.
+set -o pipefail
+
+sponge() {
+  local data
+  data="$(cat)"
+  printf '%s\n' "$data" > "$1"
+}
+
+modify() {
+  if ! "${@:2}" < "$1" | sponge "$1"
+  then
+    {
+      printf 'Failed to modify %s: ' "$1"
+      printf '%q ' "${@:2}"
+      printf '\n'
+    } >&2
+    exit 1
+  fi
+}
+
+detestify() {
+  printf '%s\n' '-- AUTOGENERATED from ShellCheck by striptests. Do not modify.'
+  awk '
+    BEGIN {
+      state = 0;
+    }
+
+    /LANGUAGE TemplateHaskell/ { next; }
+    /^import.*Test\./ { next; }
+
+    /^module/ {
+      sub(/,[^,)]*runTests/, "");
+    }
+
+    # Delete tests
+    /^prop_/ { state = 1; next; }
+
+    # ..and any blank lines following them.
+    state == 1 && /^ / { next; }
+
+    # Template Haskell marker
+    /^return / {
+      exit;
+    }
+
+    { state = 0; print; }
+    '
+}
+
+
+
+if [[ ! -e 'ShellCheck.cabal' ]]
+then
+  echo "Run me from the ShellCheck directory." >&2
+  exit 1
+fi
+
+if [[ -d '.git' ]] && ! git diff --exit-code > /dev/null 2>&1
+then
+  echo "You have local changes! These may be overwritten." >&2
+  exit 2
+fi
+
+modify 'ShellCheck.cabal' sed -e '
+  /QuickCheck/d
+  /^test-suite/{ s/.*//; q; }
+  '
+
+find . -name '.git' -prune -o -type f -name '*.hs' -print |
+  while IFS= read -r file
+  do
+    modify "$file" detestify
+  done
+

test/buildtest

@@ -0,0 +1,35 @@
+#!/bin/bash
+# This script configures, builds and runs tests.
+# It's meant for automatic cross-distro testing.
+
+die() { echo "$*" >&2; exit 1; }
+
+[ -e "ShellCheck.cabal" ] ||
+  die "ShellCheck.cabal not in current dir"
+command -v cabal ||
+  die "cabal is missing"
+
+cabal update ||
+  die "can't update"
+cabal install --dependencies-only --enable-tests ||
+  die "can't install dependencies"
+cabal configure --enable-tests ||
+  die "configure failed"
+cabal build ||
+  die "build failed"
+cabal test ||
+  die "test failed"
+
+dist/build/shellcheck/shellcheck - << 'EOF' || die "execution failed"
+#!/bin/sh
+echo "Hello World"
+EOF
+
+dist/build/shellcheck/shellcheck - << 'EOF' && die "negative execution failed"
+#!/bin/sh
+echo $1
+EOF
+
+
+echo "Success"
+exit 0

test/distrotest

@@ -0,0 +1,80 @@
+#!/bin/bash
+# This script runs 'buildtest' on each of several distros
+# via Docker.
+set -o pipefail
+
+exec 3>&1 4>&2
+die() { echo "$*" >&4; exit 1; }
+
+[ -e "ShellCheck.cabal" ] || die "ShellCheck.cabal not in this dir"
+
+[ "$1" = "--run" ] || {
+cat << EOF
+This script pulls multiple distros via Docker and compiles
+ShellCheck and dependencies for each one. It takes hours,
+and is still highly experimental.
+
+Make sure you're plugged in and have screen/tmux in place,
+then re-run with $0 --run to continue.
+
+Also note that 'dist' will be deleted.
+EOF
+exit 0
+}
+
+echo "Deleting 'dist'..."
+rm -rf dist
+
+log=$(mktemp) || die "Can't create temp file"
+date >> "$log" || die "Can't write to log"
+
+echo "Logging to $log" >&3
+exec >> "$log" 2>&1
+
+final=0
+while read -r distro setup
+do
+  [[ "$distro" = "#"* || -z "$distro" ]] && continue
+  printf '%s ' "$distro" >&3
+  docker pull "$distro" || die "Can't pull $distro"
+  printf 'pulled. ' >&3
+
+  tmp=$(mktemp -d) || die "Can't make temp dir"
+  cp -r . "$tmp/" || die "Can't populate test dir"
+  printf 'Result: ' >&3
+  < /dev/null docker run -v "$tmp:/mnt" "$distro" sh -c "
+    $setup
+    cd /mnt || exit 1
+    test/buildtest
+    "
+  ret=$?
+  if [ "$ret" = 0 ]
+  then
+    echo "OK" >&3
+  else
+    echo "FAIL with $ret. See $log" >&3
+    final=1
+  fi
+  rm -rf "$tmp"
+done << EOF
+# Docker tag          Setup command
+debian:stable         apt-get update && apt-get install -y cabal-install
+debian:testing        apt-get update && apt-get install -y cabal-install
+ubuntu:latest         apt-get update && apt-get install -y cabal-install
+opensuse:latest       zypper install -y cabal-install ghc
+
+# Older Ubuntu versions we want to support
+ubuntu:18.04          apt-get update && apt-get install -y cabal-install
+ubuntu:17.10          apt-get update && apt-get install -y cabal-install
+
+# Misc Haskell including current and latest Stack build
+ubuntu:18.10          set -e; apt-get update && apt-get install -y curl && curl -sSL https://get.haskellstack.org/ | sh -s - -f && cd /mnt && exec test/stacktest
+haskell:latest        true
+
+# Known to currently fail
+centos:latest         yum install -y epel-release && yum install -y cabal-install
+fedora:latest         dnf install -y cabal-install
+base/archlinux:latest pacman -S -y --noconfirm cabal-install ghc-static base-devel
+EOF
+
+exit "$final"

test/shellcheck.hs

@@ -0,0 +1,24 @@
+module Main where
+
+import Control.Monad
+import System.Exit
+import qualified ShellCheck.Checker
+import qualified ShellCheck.Analytics
+import qualified ShellCheck.AnalyzerLib
+import qualified ShellCheck.Parser
+import qualified ShellCheck.Checks.Commands
+import qualified ShellCheck.Checks.ShellSupport
+
+main = do
+    putStrLn "Running ShellCheck tests..."
+    results <- sequence [
+        ShellCheck.Checker.runTests,
+        ShellCheck.Checks.Commands.runTests,
+        ShellCheck.Checks.ShellSupport.runTests,
+        ShellCheck.Analytics.runTests,
+        ShellCheck.AnalyzerLib.runTests,
+        ShellCheck.Parser.runTests
+      ]
+    if and results
+      then exitSuccess
+      else exitFailure

test/stacktest

@@ -0,0 +1,27 @@
+#!/bin/bash
+# This script builds ShellCheck through `stack` using
+# various resolvers. It's run via distrotest.
+
+resolvers=(
+  nightly-"$(date -d "3 days ago" +"%Y-%m-%d")"
+)
+
+die() { echo "$*" >&2; exit 1; }
+
+[ -e "ShellCheck.cabal" ] ||
+  die "ShellCheck.cabal not in current dir"
+[ -e "stack.yaml" ] ||
+  die "stack.yaml not in current dir"
+command -v stack ||
+  die "stack is missing"
+
+stack setup        || die "Failed to setup with default resolver"
+stack build --test || die "Failed to build/test with default resolver"
+
+for resolver in "${resolvers[@]}"
+do
+  stack --resolver="$resolver" setup        || die "Failed to setup $resolver"
+  stack --resolver="$resolver" build --test || die "Failed build/test with $resolver!"
+done
+
+echo "Success"