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