How to return a failure value from a bash function

bash

Background

In this posting, the following solution was posted:

function cmakerel {
    if expr match "$PWD" '*bld*' >/dev/null ; then
        cmake -D....
    else
        echo "Wrong directory!"
    fi
}

cmakerel will invoke a cmake command, if PWD has bld in its name.

However, I normally invoke this command like: cmakerel && make check

Question

How do I modify the code above so that it returns a value on failure such that the second part, make check does not get invoked?

Probably returning some kind of non-zero value should work.

Best Answer

Add

return $?

below the cmake call to exit the function with the same exit code as cmake, and add

return 1

below the echo call to exit with 1, which is non-zero and therefore indicates an error.

You can alternatively (if you call both commands in combination) add the make call to this function:

 cmake [args] && make -j4

Or, to allow e.g. for more fine-grained error handling:

cmake [args]
local _ret=$?
if [ $_ret -ne 0 ] ; then
   echo "cmake returned with exit code $_ret, aborting!" >&2
   return $_ret
fi
make -j4

If you call it as a standalone program, i.e. store the function in a shell script, and invoke e.g. as

/path/to/cmakerel.sh

then you can use exit instead of return to abort the whole program/subshell.

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