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Give more examples of what ShellCheck looks for

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Vidar Holen 2021-10-15 15:29:52 -07:00
parent 788aee1b7c
commit 7b2092b3cd
1 changed files with 11 additions and 1 deletions
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@ -358,6 +358,7 @@ echo 'Don't forget to restart!' # Singlequote closed by apostrophe
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
unset var[i] # Array index treated as glob
``` ```
### Conditionals ### Conditionals
@ -376,6 +377,7 @@ 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 ((..))
[ x ] & [ y ] | [ z ] # Accidental backgrounding and piping
``` ```
### Frequently misused commands ### Frequently misused commands
@ -447,6 +449,8 @@ echo "Hello $name" # Unassigned lowercase variables
cmd | read bar; echo $bar # Assignments in subshells cmd | read bar; echo $bar # Assignments in subshells
cat foo | cp bar # Piping to commands that don't read cat foo | cp bar # Piping to commands that don't read
printf '%s: %s\n' foo # Mismatches in printf argument count printf '%s: %s\n' foo # Mismatches in printf argument count
eval "${array[@]}" # Lost word boundaries in array eval
for i in "${x[@]}"; do ${x[$i]} # Using array value as key
``` ```
### Robustness ### Robustness
@ -471,6 +475,7 @@ ShellCheck will warn when using features not supported by the shebang. For examp
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
expr match str regex # Unportable alias for `expr str : regex`
trap 'exit 42' sigint # Unportable signal spec trap 'exit 42' sigint # Unportable signal spec
cmd &> file # Unportable redirection operator cmd &> file # Unportable redirection operator
read foo < /dev/tcp/host/22 # Unportable intercepted files read foo < /dev/tcp/host/22 # Unportable intercepted files
@ -491,10 +496,15 @@ rm “file” # Unicode quotes
echo "Hello world" # Carriage return / DOS line endings echo "Hello world" # Carriage return / DOS line endings
echo hello \ # Trailing spaces after \ echo hello \ # Trailing spaces after \
var=42 echo $var # Expansion of inlined environment var=42 echo $var # Expansion of inlined environment
#!/bin/bash -x -e # Common shebang errors !# bin/bash -x -e # Common shebang errors
echo $((n/180*100)) # Unnecessary loss of precision echo $((n/180*100)) # Unnecessary loss of precision
ls *[:digit:].txt # Bad character class globs ls *[:digit:].txt # Bad character class globs
sed 's/foo/bar/' file > file # Redirecting to input sed 's/foo/bar/' file > file # Redirecting to input
var2=$var2 # Variable assigned to itself
[ x$var = xval ] # Antiquated x-comparisons
ls() { ls -l "$@"; } # Infinitely recursive wrapper
alias ls='ls -l'; ls foo # Alias used before it takes effect
for x; do for x; do # Nested loop uses same variable
while getopts "a" f; do case $f in "b") # Unhandled getopts flags while getopts "a" f; do case $f in "b") # Unhandled getopts flags
``` ```