Case statement fallthrough?

Question

In popular imperative languages, switch statements generally \"fall through\" to the next level once a case statement has been matched.

Example:

int         


        

Answer 1

Try this:

case $VAR in
normal)
    echo "This doesn't do fallthrough"
    ;;
fallthrough)
    echo -n "This does "
    ;&
somethingelse)
    echo "fall-through"
    ;;
esac

Answer 2

The ;& and ;;& operators were introduced in bash 4.0, so if you want to stick with a five year old version of bash, you'll either have to repeat code, or use ifs.

if (( a == 1)); then echo quick; fi
if (( a > 0 && a <= 2)); then echo brown; fi 
if (( a > 0 && a <= 3)); then echo fox; fi
if (( a == 4)); then echo jumped; fi

or find some other way to achieve the actual goal.

(On a side note, don't use all uppercase variable names. You risk overwriting special shell variables or environment variables.)

Answer 3

Using ;& is not very portable, as it requires bash (not ash, dash, or any other minimal sh) and it requires at least bash 4.0 or newer (not available on all systems, e.g. macOS 10.14.6 still only offers bash 3.2.57).

A work around that I consider much nicer to read than a lot of if's is loop and modify the case var:

#!/bin/sh

A=2
A_BAK=$A
while [ -n "$A" ]; do
    case $A in
        1)
            echo "QUICK"
            A=2
            ;;

        2)
            echo "BROWN"
            A=3
            ;;

        3)
            echo "FOX"
            A=4
            ;;

        4)
            echo "JUMPED"
            A=""
            ;;
    esac
done
A=$A_BAK