Linux and Unix Shell Programming

18.4. Case statement

The case statement is a multiple-choice statement. You use case statements to match a value against a pattern. If the match is successful, you can execute commands based purely on this match. Here’s the format of the ‘ case ’ statement:

case value in pattern1)   commands1  ...  ;; pattern2)   commands2  ...  ;; esac 

Here’s how case works. The word after the value must be ‘in’, and each pattern must be terminated with a right bracket. The value can be a variable or a constant. When a match is found against a pattern all commands are then executed for that pattern up to the ;;.

The value will check each pattern for a match. Once a pattern is matched, it will not continue with the other patterns even after it has executed ...