#!/bin/sh

user=$1
shift

case "$user" in
	''|-*)
		echo >&2 "Bad/evil user name."
		exit 1
		;;
esac

if [ $# -eq 0 ]; then
	exec su - "$user"
else
	exec su -s '/bin/sh' - "$user" -- -l -c 'exec "$@"' -- "$@"
fi