Life of a Sysadmin

The occassional trials and tribulations of a jack of all tr ades sysadmin in a startup in Silicon Valley

March 2007

x11vnc, or How to Recover from a wedged X session

An engineer came to me complaining that his X session was wedged. My immediate reaction (without looking up from my work) has become a standard response; "Ctrl, Alt, Backspace to kill the X server and once you log back in set the screensaver to just power off the monitors."

This paricularly engineer however had a couple of long running tasks in terminal windows that he didn't wish to lose, as they had been running for nearly 8 hours; and could I please help him fix the X session? He couldn't just let the machine sit until the tasks were done, and than kill the X server as he needed to see the output of the jobs that were running.

Tangent: Why do so few people understand that when running tasks that are going to take awhile, the output should be redirected to a file (or perhaps a file and stdout with the tee command) so that if the computer were to crash mid run, at least the output would be saved. Not even a bad experience or two (resulting in lost output) seems to convince people of this need.

In this particular instance, the X server wasn't horked far enough to stop x11vnc (which takes a running X session and exports it as a VNC session) from working. This technique won't work on all X server breakages (or even most in my experience), but it does work on occassion.

[2007/03/23 | /software | permanent link]