Question

Google has finally failed me. I cannot seem to find how to do this in Bourne shell scripting:

I am writing a shell script to handle all of my testing for a project. I’ve set up functions for each task that this script could do (build, run, clean, etc), and would like to pass any additional command-line parameters (besides the command itself) onto the desired function.

Example:

./test.sh build -j should pass -j into the build function.

A pseudo-code version of this logic would look like:

function build() {
   make $*
}

if [ $1 == 'build' ]; then
   build $2 -> $N
fi

How can I accomplish this?

Answer 1

I think you could achieve this effect using the shift command. It will move all of the positional parameters down one place and drops the value of $1 (so the value of $3 gets moved to $2, the value of $2 gets moved to $1 and the value of $1 is lost). Once you’ve done that you can just use $@ to pick up the list of arguments you’re actually interested in e.g.

function build() {
    echo "build with $@"
}

echo "Starting args are $@"
cmd=$1
shift

if [ "$cmd" = 'build' ]; then
    build "$@"
fi