Pattern: Use of unquoted variable in case branch pattern
Issue: -
When unquoted variables and command expansions are used in case branch patterns, they will be interpreted as globs.
This can lead to some surprising behavior, such as case $x in $x) trigger;; esac
not triggering in some cases, such as when x='Pride and Prejudice [1813].epub'
.
To match the literal content of the variable or expansion, make sure to double quote the expansion.
Example of incorrect code:
case $input in
- ) echo "Reading from stdin..." ;;
$output ) echo "Input should be different from output" ;;
esac
Example of correct code:
case $input in
- ) echo "Reading from stdin..." ;;
"$output" ) echo "Input should be different from output" ;;
esac