Add tentative implementation of spawn(8)

spawn.sh

@@ -0,0 +1,34 @@
+#!/bin/sh
+set -eu
+
+die() {
+	echo "${0}:" "$@" >&2
+	exit 1
+}
+
+: ${SPAWND_PIPE:=/var/run/spawnd.pipe}
+
+while getopts 'c:' opt; do
+	case "${opt}" in
+		(c) SPAWND_PIPE=$OPTARG;;
+		(?) exit 1;;
+	esac
+done
+shift $((OPTIND - 1))
+
+if ! [ -p "${SPAWND_PIPE}" ]; then
+	die "${SPAWND_PIPE} is not a named pipe"
+fi
+
+[ $# -lt 1 ] && die 'action required'
+[ $# -lt 2 ] && die 'service name required'
+
+action=$(echo "${1}" | tr 'A-Z' 'a-z')
+for valid in start stop restart status $(kill -l | tr 'A-Z' 'a-z'); do
+	[ "${action}" = "${valid}" ] && break
+done
+if [ "${action}" != "${valid}" ]; then
+	die "${action} is not a valid action or signal"
+fi
+
+echo "$@" > "${SPAWND_PIPE}"