Regex in case statement

Question

I'm having a hard time getting regex matches to work in a bash case statement.

Example code:

#!/bin/bash                          

str='    word1 word2'

echo "With grep:"
echo "$str" |grep '^\s*\<word1\>'

echo "With case:"
case "$str" in
    '^\s*\<word1\>') echo "$str" ;;
esac

The example works with grep, but not with case... I'm confused, because some simpler regexes work with case. Does case use a different syntax for regex? Am I just not escaping things properly?

Solution

That is because case doesn't use regex's but bash Pathname Expansion. You can learn more from bash man page or from Bash Reference Manual.

Comments

[heemayl]

case does not support regex, it supports shell globbing.

[Conner Dassen]

Great to link to the manual.