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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 ?
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Since version 3 (circa 2004), bash has a built-in regular expression comparison operator, represented by =~. A lot of scripting tricks that use grep or sed can now be handled by bash expressions and the bash expressions might just give you scripts that are easier to read and maintain.
The case statement starts with the case keyword followed by the $variable and the in keyword. The statement ends with the case keyword backwards - esac . The script compares the input $variable against the patterns in each clause until it finds a match.
A regular expression (regex) is a text pattern that can be used for searching and replacing. Regular expressions are similar to Unix wild cards used in globbing, but much more powerful, and can be used to search, replace and validate text.
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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