Hello all

Bumped into something I needed to do this morning, thought others may be interested.

I needed to get an accurate count of how many 15 inch monitors I had on my LTSP network. One can, of course, get this from xdpyinfo, but I can't ssh into clients to do this. What to do, what to do...

Well, of course, what I need to do is set my $DISPLAY and $XAUTHORITY environment variables correctly, so I can run xdpyinfo. But, how to find out who's on what terminal?

Well, since everyone runs metacity as a window manager:

pgrep metacity

returns a list of process id's. From there, we can look in /proc/<pid>/environ, and get some more info! But hold on:

cat /proc/3660/environ

returns: SSH_CLIENT=192.168.0.229 443422USER=foobarMAIL=/var/mail/foobarGNOME_KEYRING_SOCKET=/tmp/keyring-awvD15/socketSSH_AGENT_PID=3510

etc. Environment variables are null terminated! So, how to get around that?

As usual, there's a quick easy way to do it: tr to the rescue:

cat /proc/3660/environ | tr '\0' '\n'

SSH_CLIENT=192.168.0.229 4434 22 USER=foobar MAIL=/var/mail/foobar GNOME_KEYRING_SOCKET=/tmp/keyring-awvD15/socket

etc.

Hey! Fit for using with eval! Here's the whole script, just for fun.

#!/bin/bash

for PROC in $(pgrep metacity); do eval $(cat /proc/$PROC/environ | tr '\0' '\n' | grep SSH_CLIENT | awk '{print $1}') eval $(cat /proc/$PROC/environ | tr '\0' '\n' | grep USER)

export DISPLAY=$SSH_CLIENT:6 export XAUTHORITY=/usr/legal/home/$USER/.Xauthority echo -n ${USER} xdpyinfo | grep dimension done

Hope someone finds this useful.

Scott