function usage() {
    echo "Usage: $0 [OPTION]..."
    echo "  -h, --help      you're reading it"
    echo "  -d, --droid-hal build droid-hal-device (rpm/)"
    echo "  -c, --configs   build droid-configs"
    echo "  -m, --mw[=REPO] build HW middleware packages or REPO"
    echo "  -v, --version   build droid-hal-version"
    echo "  -b, --build=PKG build one package (PKG can include path)"
    echo "  -s, --spec=SPEC optionally used with -m or -b"
    echo "                  can be supplied multiple times to build multiple .spec files at once"
    echo "  -D, --do-not-install"
    echo "                  useful when package is needed only in the final image"
    echo "                  especially when it conflicts in an SDK target"
    echo " No options assumes building for all areas."
    exit 1
}