#! /bin/sh -ex

dir=west bogus=nil
usage () { echo "usage: $0 [-ensw] HOST:RDPY/LDPY"; }
while getopts "hensw" opt; do
  case $opt in
    h) usage; exit ;;
    e) dir=east ;;
    n) dir=north ;;
    s) dir=south ;;
    w) dir=west ;;
    *) bogus=t ;;
  esac
done
shift $(( $OPTIND - 1))
case $bogus,$#,$1 in nil,1,*:*/*) ;; *) usage >&2; exit 2 ;; esac
host=${1%:*} dpy=${1##*:}; rdpy=${dpy%%/*} ldpy=${dpy#*/}
control=ControlPath=~/.ssh/sock-%l/control-%r@%h.x2x
ssh -o$control -L"/tmp/.X11-unix/X$ldpy:/tmp/.X11-unix/X$rdpy" -Nafx "$host"
sleep 1
trap 'trap - INT QUIT HUP EXIT; ssh -o$control -Oexit "$host"; rm -f "/tmp/.X11-unix/X$ldpy"' INT QUIT HUP EXIT
x2x -$dir -to ":$ldpy"