Bash Quick Start Guide

Switching with the case keyword

Bash's extension to string equality tests for pattern matching is useful, but it can sometimes be more convenient to use the older POSIX-specified case construct, which is shell script's analogue of the C switch statement.

The case statement allows us to run commands based on the outcome of matching a string against glob patterns. For example, to check whether the command variable matches help, we might do this:

case $command in
    help) printf 'Command help:\n...' ;;
esac

Note the following details of this syntax:

• You don't have to double-quote $command just after the case statement.
• The pattern to match has a closing ), but does not require an opening one.
• The closing keyword is esac, which is case spelled ...