#!/bin/sh

set -e
[ -n "$DEBUG" ] && set -x

append=
while getopts ah opt; do
	case "$opt" in
	a) append=1 ;;
	h | ?)
		printf "usage: %s [-ah]\n\n" "$(basename "$0")"
		exit 2
		;;
	esac
done
shift $((OPTIND - 1))
outname=$1

tmpfile=$(mktemp)
trap '{ rm "$tmpfile"; }' EXIT

cat - >"$tmpfile"

if [ -n "$outname" ]; then
	(
		if [ -n "$append" ]; then
			tee -a "$outname" >/dev/null
		else
			tee "$outname" >/dev/null
		fi
	) <"$tmpfile"
else
	cat "$tmpfile"
fi