#!/usr/bin/env bash

## Run a command as a background process.
##
## Usage: background <command> [<command_arg>...]
##
## Dependencies: GNU coreutils, GNU sed
##
## I use this script to run GUI apps via aliases and window manager key bindings
## (I don't use an application launcher). This script isn't needed to run apps
## via my window manager, but without this script, those apps will be
## subprocesses of the window manager; whereas, after `background <command>` has
## run, the <command> process is orphaned and becomes a child of the init
## process, which I prefer for GUI apps.

set -euo pipefail
shopt -s inherit_errexit

die() { echo -e "$(basename "$0"): $1" >&2; exit 1; }

[[ " $* " =~ ' --help ' ]] && sed -n 's/^## *//p' "$0" && exit
(( $# >= 1 )) || die 'missing argument'

cmd=$1; type "$cmd" &> /dev/null || die "command not found: $cmd"
cmd_args=("${@:2}")

$cmd "${cmd_args[@]}" &> /dev/null &