array_as_default_arg.bash

#!/bin/bash

REPOS=(foo bar)

git_up() {
        if (( $# > 0 ))
        then
                repos=$@
        else
                repos=${REPOS[@]}
        fi
        for repo in "${repos[@]}"
        do

                cd "$repo"
                git pull --rebase
        done
}

cmd="$1"
shift 1

case "$cmd"
in
        git_up)
                git_up "$@"
                ;;
        *)
                echo "Usage: $0 git_up [projects...]"
                exit 1
                ;;
esac