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Merge pull request #1026 from PeterDaveHello/patch-1 

Enable syntax highlight in README.md code block
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koalaman 2017-10-15 19:09:32 -07:00 committed by GitHub
parent 1491402dcb 76ad5dbb9f
commit 5d9cb81008
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README.md
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@ -148,8 +148,10 @@ On Solus:
From Docker Hub: From Docker Hub:
```sh
docker pull koalaman/shellcheck:latest # Or :v0.4.6 for a release version docker pull koalaman/shellcheck:latest # Or :v0.4.6 for a release version
docker run -v "$PWD:/mnt" koalaman/shellcheck myscript docker run -v "$PWD:/mnt" koalaman/shellcheck myscript
```
or use `koalaman/shellcheck-alpine` if you want a larger Alpine Linux based image to extend. or use `koalaman/shellcheck-alpine` if you want a larger Alpine Linux based image to extend.
@ -209,12 +211,16 @@ 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`): Add this directory to your `PATH` (for bash, add this to your `~/.bashrc`):
```sh
export PATH="$HOME/.cabal/bin:$PATH" export PATH="$HOME/.cabal/bin:$PATH"
```
Log out and in again, and verify that your PATH is set up correctly: Log out and in again, and verify that your PATH is set up correctly:
```sh
$ which shellcheck $ which shellcheck
~/.cabal/bin/shellcheck ~/.cabal/bin/shellcheck
```
On native Windows, the `PATH` should already be set up, but the system 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, may use a legacy codepage. In `cmd.exe`, `powershell.exe` and Powershell ISE,
@ -242,6 +248,7 @@ So what kind of things does ShellCheck look for? Here is an incomplete list of d
ShellCheck can recognize several types of incorrect quoting: ShellCheck can recognize several types of incorrect quoting:
```sh
echo $1 # Unquoted variables echo $1 # Unquoted variables
find . -name *.ogg # Unquoted find/grep patterns find . -name *.ogg # Unquoted find/grep patterns
rm "~/my file.txt" # Quoted tilde expansion rm "~/my file.txt" # Quoted tilde expansion
@ -252,11 +259,13 @@ ShellCheck can recognize several types of incorrect quoting:
echo 'Don\'t try this at home' # Attempting to escape ' in '' echo 'Don\'t try this at home' # Attempting to escape ' in ''
echo 'Path is $PATH' # Variables in single quotes echo 'Path is $PATH' # Variables in single quotes
trap "echo Took ${SECONDS}s" 0 # Prematurely expanded trap trap "echo Took ${SECONDS}s" 0 # Prematurely expanded trap
```
### Conditionals ### Conditionals
ShellCheck can recognize many types of incorrect test statements. ShellCheck can recognize many types of incorrect test statements.
```sh
[[ n != 0 ]] # Constant test expressions [[ n != 0 ]] # Constant test expressions
[[ -e *.mpg ]] # Existence checks of globs [[ -e *.mpg ]] # Existence checks of globs
[[ $foo==0 ]] # Always true due to missing spaces [[ $foo==0 ]] # Always true due to missing spaces
@ -268,11 +277,13 @@ ShellCheck can recognize many types of incorrect test statements.
[ grep -q foo file ] # Command without $(..) [ grep -q foo file ] # Command without $(..)
[[ "$$file" == *.jpg ]] # Comparisons that can't succeed [[ "$$file" == *.jpg ]] # Comparisons that can't succeed
(( 1 -lt 2 )) # Using test operators in ((..)) (( 1 -lt 2 )) # Using test operators in ((..))
```
### Frequently misused commands ### Frequently misused commands
ShellCheck can recognize instances where commands are used incorrectly: ShellCheck can recognize instances where commands are used incorrectly:
```sh
grep '*foo*' file # Globs in regex contexts grep '*foo*' file # Globs in regex contexts
find . -exec foo {} && bar {} \; # Prematurely terminated find -exec find . -exec foo {} && bar {} \; # Prematurely terminated find -exec
sudo echo 'Var=42' > /etc/profile # Redirecting sudo sudo echo 'Var=42' > /etc/profile # Redirecting sudo
@ -283,11 +294,13 @@ ShellCheck can recognize instances where commands are used incorrectly:
exec foo; echo "Done!" # Misused 'exec' exec foo; echo "Done!" # Misused 'exec'
find -name \*.bak -o -name \*~ -delete # Implicit precedence in find find -name \*.bak -o -name \*~ -delete # Implicit precedence in find
f() { whoami; }; sudo f # External use of internal functions f() { whoami; }; sudo f # External use of internal functions
```
### Common beginner's mistakes ### Common beginner's mistakes
ShellCheck recognizes many common beginner's syntax errors: ShellCheck recognizes many common beginner's syntax errors:
```sh
var = 42 # Spaces around = in assignments var = 42 # Spaces around = in assignments
$foo=42 # $ in assignments $foo=42 # $ in assignments
for $var in *; do ... # $ in for loop variables for $var in *; do ... # $ in for loop variables
@ -298,11 +311,13 @@ ShellCheck recognizes many common beginner's syntax errors:
echo "Argument 10 is $10" # Positional parameter misreference echo "Argument 10 is $10" # Positional parameter misreference
if $(myfunction); then ..; fi # Wrapping commands in $() if $(myfunction); then ..; fi # Wrapping commands in $()
else if othercondition; then .. # Using 'else if' else if othercondition; then .. # Using 'else if'
```
### Style ### Style
ShellCheck can make suggestions to improve style: ShellCheck can make suggestions to improve style:
```sh
[[ -z $(find /tmp | grep mpg) ]] # Use grep -q instead [[ -z $(find /tmp | grep mpg) ]] # Use grep -q instead
a >> log; b >> log; c >> log # Use a redirection block instead a >> log; b >> log; c >> log # Use a redirection block instead
echo "The time is `date`" # Use $() instead echo "The time is `date`" # Use $() instead
@ -311,11 +326,13 @@ ShellCheck can make suggestions to improve style:
echo $(($RANDOM % 6)) # Don't use $ on variables in $((..)) echo $(($RANDOM % 6)) # Don't use $ on variables in $((..))
echo "$(date)" # Useless use of echo echo "$(date)" # Useless use of echo
cat file | grep foo # Useless use of cat cat file | grep foo # Useless use of cat
```
### Data and typing errors ### Data and typing errors
ShellCheck can recognize issues related to data and typing: ShellCheck can recognize issues related to data and typing:
```sh
args="$@" # Assigning arrays to strings args="$@" # Assigning arrays to strings
files=(foo bar); echo "$files" # Referencing arrays as strings files=(foo bar); echo "$files" # Referencing arrays as strings
declare -A arr=(foo bar) # Associative arrays without index declare -A arr=(foo bar) # Associative arrays without index
@ -324,22 +341,26 @@ ShellCheck can recognize issues related to data and typing:
var=World; echo "Hello " var # Unused lowercase variables var=World; echo "Hello " var # Unused lowercase variables
echo "Hello $name" # Unassigned lowercase variables echo "Hello $name" # Unassigned lowercase variables
cmd | read bar; echo $bar # Assignments in subshells cmd | read bar; echo $bar # Assignments in subshells
```
### Robustness ### Robustness
ShellCheck can make suggestions for improving the robustness of a script: ShellCheck can make suggestions for improving the robustness of a script:
```sh
rm -rf "$STEAMROOT/"* # Catastrophic rm rm -rf "$STEAMROOT/"* # Catastrophic rm
touch ./-l; ls * # Globs that could become options touch ./-l; ls * # Globs that could become options
find . -exec sh -c 'a && b {}' \; # Find -exec shell injection find . -exec sh -c 'a && b {}' \; # Find -exec shell injection
printf "Hello $name" # Variables in printf format printf "Hello $name" # Variables in printf format
for f in $(ls *.txt); do # Iterating over ls output for f in $(ls *.txt); do # Iterating over ls output
export MYVAR=$(cmd) # Masked exit codes export MYVAR=$(cmd) # Masked exit codes
```
### Portability ### Portability
ShellCheck will warn when using features not supported by the shebang. For example, if you set the shebang to `#!/bin/sh`, ShellCheck will warn about portability issues similar to `checkbashisms`: ShellCheck will warn when using features not supported by the shebang. For example, if you set the shebang to `#!/bin/sh`, ShellCheck will warn about portability issues similar to `checkbashisms`:
```sh
echo {1..$n} # Works in ksh, but not bash/dash/sh echo {1..$n} # Works in ksh, but not bash/dash/sh
echo {1..10} # Works in ksh and bash, but not 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 echo -n 42 # Works in ksh, bash and dash, undefined in sh
@ -350,11 +371,13 @@ ShellCheck will warn when using features not supported by the shebang. For examp
[ $UID = 0 ] # Variable undefined in dash/sh [ $UID = 0 ] # Variable undefined in dash/sh
local var=value # local is undefined in sh local var=value # local is undefined in sh
time sleep 1 | sleep 5 # Undefined uses of 'time' time sleep 1 | sleep 5 # Undefined uses of 'time'
```
### Miscellaneous ### Miscellaneous
ShellCheck recognizes a menagerie of other issues: ShellCheck recognizes a menagerie of other issues:
```sh
PS1='\e[0;32m\$\e[0m ' # PS1 colors not in \[..\] PS1='\e[0;32m\$\e[0m ' # PS1 colors not in \[..\]
PATH="$PATH:~/bin" # Literal tilde in $PATH PATH="$PATH:~/bin" # Literal tilde in $PATH
rm “file” # Unicode quotes rm “file” # Unicode quotes
@ -365,6 +388,7 @@ ShellCheck recognizes a menagerie of other issues:
echo $((n/180*100)) # Unnecessary loss of precision echo $((n/180*100)) # Unnecessary loss of precision
ls *[:digit:].txt # Bad character class globs ls *[:digit:].txt # Bad character class globs
sed 's/foo/bar/' file > file # Redirecting to input sed 's/foo/bar/' file > file # Redirecting to input
```
## Testimonials ## Testimonials