script-cmd-dir

#!/bin/bash
# Print command to obtain script directory from inside a script

# Short version
# src: https://stackoverflow.com/a/246128/4419816
CMD='SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )'


# Long version
get_script_dir()
{
    # src: https://stackoverflow.com/a/246128/4419816
    local SOURCE=${BASH_SOURCE[0]}
    local DIR
    # Resolve ${SOURCE} until the file is no longer a symlink
    while [ -L "${SOURCE}" ]; do
        DIR=$( cd -P "$( dirname "${SOURCE}" )" >/dev/null 2>&1 && pwd )
        SOURCE=$(readlink "${SOURCE}")
        # If ${SOURCE} was a relative symlink, we need to resolve it
        # relative to the path where the symlink file was located
        [[ "${SOURCE}" != /* ]] && SOURCE="${DIR}/${SOURCE}"
    done
    ( cd -P "$( dirname "${SOURCE}" )" >/dev/null 2>&1 && pwd )
}


NAME="$(basename "${0}")"
USAGE="usage: ${NAME} (short|long|test|help)"


main()
{
    case "${1}" in
        "short")
            echo "${CMD}"
        ;;
        "long")
            declare -f get_script_dir
        ;;
        "test")
            echo -e "\n$ ${NAME} help"
            "${0} help"
    
            echo -e "\n$ ${NAME} short"
            "${0}" short
    
            echo -e "\n$ ${NAME} long"
            "${0}" long
    
            echo -e "\n$ eval \"\$(${NAME} short)\" && echo \"\${SCRIPT_DIR}\""
            eval "$(${0} short)" && echo ${SCRIPT_DIR}
    
            echo -e "\n$ eval \"\$(${NAME} long)\" && get_script_dir"
            eval "$(${0} long)" && get_script_dir
        ;;
        ""|"help")
            echo "${USAGE}" >&2
            return 1
        ;;
        *)
            echo "${USAGE}" >&2
            echo -e "\nerror: wrong argument: ${1}" >&2
            return 1
        ;;
    esac
}


main "${@}"