Regular expressions in a Bash case statement

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 :-)

If you want assert that * really matches digits in ws*.host.com and want to use case instead of if, elif, elif...you can use something like that:

case $SERVER in  ws-[0123456789][0123456789][0123456789].host.com) echo "Web Server" ;;  db-[0123456789][0123456789][0123456789].host.com) echo "DB server" ;;  bk-[0123456789][0123456789][0123456789].host.com) echo "Backup server" ;;  *) echo "Unknown server" ;;esac

But that does not work for more than 999 servers.

If I had to make a script for this use case, I probably write something like that (because I love regexes and case syntax ;) ):

srv=`expr "$SERVER" : '^\(db\|bk\|ws\)-[0-9]\+\.host\.com$'`echo -n "$SERVER : "case $srv in  ws) echo "Web Server" ;;  db) echo "DB server" ;;  bk) echo "Backup server" ;;  *) echo "Unknown server !!!"esac

case can only use globs. If you want to do regex matching then you'll need to use a series of if-then-else-elif-fi statements, with [[.