Regular expressions in a Bash case statement

regex bash case glob
Unni picture Unni · Mar 9, 2012 · Viewed 75.1k times · Source

I am using following script, which uses case statement to find the server. 

    #!/bin/bash
SERVER=$1;
echo $SERVER | egrep "ws-[0-9]+\.host\.com";
case $SERVER in
ws-[0-9]+\.host\.com) echo "Web Server"
;;
db-[0-9]+\.host\.com) echo "DB server"
;;
bk-[0-9]+\.host\.com) echo "Backup server"
;;
*)echo "Unknown server"
;;
esac

But it is not working. Regex is working with egrep but not with case. sample O/P

./test-back.sh ws-23.host.com
ws-23.host.com
Unknown server

Any Idea ?

Answer

che picture che · Mar 9, 2012

Bash case does not use regular expressions, but shell pattern matching only.

Therefore, instead of regex ws-[0-9]+\.host\.com you should use pattern ws*.host.com (or ws-+([0-9]).host.com, but that looks a bit advanced and I've never tried that :-)

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