Conditionally executing a script and using return value

[Thomas Nyberg]

Hello,

I would like my Makefile to:

        1. Check if a variable is set to specific value,
        2. If it is, execute a script and get its return value,
        3. Stop executing Makefile depending upon return value.

Here is the Makefile I have:

`Makefile`
-------------------------------------------------------------
    FORCE=true

    all: check_force
        @echo "success"

    check_force:
        ifeq ($(FORCE),true)
        $(shell sh ./prompt.sh)
        endif
-------------------------------------------------------------

and here is the `prompt.sh` file:

`prompt.sh`
-------------------------------------------------------------
    while true;
    do
        read -p "Are you sure you want force to be \"true\"? (y/n) " resp
        case $resp in
            [Yy]* ) echo "You picked yes"; exit 0;;
            [Nn]* ) echo "You picked no"; exit 1;;
            * ) echo "You picked nonsense";;
        esac
    done
-------------------------------------------------------------

I have tried many different variations of this with various 
errors/problems, but basically I would like to stop execution if FORCE 
is set to "true" and if the user selects "n" in the prompt. If the user 
selects "y" I would like things to continue (in this case simply echo 
"success"). If FORCE is not set to "true", I don't want the script to 
execute at all.

Thanks for any help! Ask for more details if I'm not making sense...

Cheers,
Thomas