how to use case in bash code example

Example 1: bash case statement

case "$1" in
        start)
            start ;;
        stop)
            stop ;;
        restart)
            stop; start ;;
        *)
            echo $"Usage: $0 {start|stop|restart}"
            exit 1
esac

Example 2: bash case statement

case expression in
    pattern1 )
        statements ;;
    pattern2 )
        statements ;;
    ...
esac