#!/bin/sh

SED="/usr/bin/sed"
CAT="/bin/cat"

dispnum=0
if [ ! -z "${DISPLAY}" ]; then
    dispnum=$(echo ${DISPLAY} | ${SED} -E -e 's|:([0-9]+).*|\1|')
fi

if [ ! -f "/tmp/.X${dispnum}-lock" ]; then
    echo "ERROR: Failed to find X lock file for display ${dispnum}"
    exit 1
fi
pid=$(${CAT} "/tmp/.X${dispnum}-lock")

echo ${pid}