bash file that can be sourced or executed. knows where to look for files

sourceable_bash_with_curdir.sh

#!/usr/bin/env bash

CURDIR=${PWD}
COMMAND="${BASH_SOURCE:-$0}"
TARGET=$(basename $COMMAND)
TARGET_DIR="$( cd "$(dirname $COMMAND)" ; pwd -P )"

function main() {
    echo "Hello ${@}"
    echo "Curdir = ${CURDIR}"
    echo "Command = ${COMMAND}"
    echo "Target dir (pwd) = ${TARGET_DIR}"
    echo "Target = ${TARGET}"
}

# Execute function if file is not being sourced
[[ $0 != "$BASH_SOURCE" ]] || main $@

Execute as bash script

$ ./workspace/project/tmp.sh f a

Hello f a
Curdir = /Users/home/you
Command = ./workspace/project/tmp.sh
Target dir (pwd) = /Users/home/you/workspace/project
Target = tmp.sh

Source script

$ source ./workspace/project/tmp.sh
$ main f a

Hello f a
Curdir = /Users/home/you
Command = ./workspace/project/tmp.sh
Target dir (pwd) = /Users/home/you/workspace/project
Target = tmp.sh