system-upgrade: use screen

# Smart way to update your archlinux system

SCREEN=screen

PACMAN_OPTS=()

# run system upgrade and checkservices

upgrade() {

		if pacman --sync --refresh --sysupgrade "${PACMAN_OPTS[@]}"; then

			checkservices

		else

			printf '\e[7;33;40mcheckservices not run because pacman did not exit zero\e[m\n'

		fi

}

# We need to be root

enforce_root() {

	if (( $UID != 0 )); then

		if type -P sudo >/dev/null; then

			exec sudo -- "$0" "$@"

		elif type -P su >/dev/null; then

		exec su -l -c "$0" "$@"

			exec su -c "$0" "$@"

		fi

		printf '\e[7;31;40mYou need to be root\e[m\n'

		exit 1

	fi

}

if pacman --sync --refresh --sysupgrade "$@"; then

	checkservices

else

	printf '\e[7;33;40mcheckservices not run because pacman did not exit zero\e[m\n'

# display application usage and exit 1

usage() {

    echo "usage ${0##*/} [options] -- [pacman options]"

    echo "description: archlinux system upgrade with checkservices"

    echo 'options:'

    echo '  -h: this help' >&2

    echo "  -S: no screen" >&2

    exit 1

}

# parse command line arguments

# set options as global vars

argparse() {

    local opt

    while getopts 'hS' opt; do

        case $opt in

            S) SCREEN=0;;

            *) usage;;

        esac

    done

    shift $((OPTIND - 1));

    PACMAN_OPTS=("$@")

}

# emulated program entry point

main() {

    # parse command line options

    argparse "$@"

		# be root

		enforce_root "$@"

		if [[ "$SCREEN" ]] && type -P $SCREEN >/dev/null; then

			exec $SCREEN "$0" -S "$@"

		fi

		# relly do the job

		upgrade

}

main "$@"