env/bin/plumb.sh

#!/bin/sh
# plumb
# Written in 2020 by Lucas
# CC0 1.0 Universal/Public domain - No rights reserved
#
# To the extent possible under law, the author(s) have dedicated all
# copyright and related and neighboring rights to this software to the
# public domain worldwide. This software is distributed without any
# warranty. You should have received a copy of the CC0 Public Domain
# Dedication along with this software. If not, see
# <http://creativecommons.org/publicdomain/zero/1.0/>.

usage()
{
	printf "Usage: %s [-T] [URI|file]\n" "${0##*/}">&2
	exit 1
}

err()
{
	printf "%s: %s\n" "${0##*/}" "$*" >&2
	exit 1
}

check_required_program()
{
	command -v "$1" >/dev/null 2>&1 || err "$1: program not found"
}

check_required_program fetch

Tflag=
while getopts T flag; do
	case $flag in
	T)	Tflag=-T
		;;
	*)	usage
		;;
	esac
done
shift $((OPTIND - 1))

[ $# -le 1 ] || usage

target=
if [ $# -eq 1 ]; then
	target=$1
else
	IFS= read -r target
fi

[ -n "$target" ] || usage

case $target in
http://* | https://*)
	file=$(fetch $Tflag "$target") || err "couldn't fetch $target"
	;;
*)	[ -f "$target" ] || err "can't handle $uri"
	file=$target
	;;
esac

mimetype=$(file -bi "$file")
case $mimetype in
audio/*)
	check_required_program mpv
	mpv --no-video "$file"
	;;
image/*)
	check_required_program sxiv
	sxiv "$file"
	;;
text/html)
	check_required_program w3m
	check_required_program xterm
	xterm -e w3m -T text/html "$file"
	;;
text/plain | application/x-shellscript)
	check_required_program ${PAGER:-less}
	check_required_program xterm
	xterm -e ${PAGER:-less} "$file"
	;;
video/*)
	check_required_program mpv
	mpv "$file"
	;;
*)	err "don't know how to open $mimetype"
	;;
esac