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X Display Manager Repair & Removal Pre-shrunk Ultra-Mini HOWTO

X has started and (pick one or more):

This document is about how to fix this....

Note: several of the commands and directory structures used in this document are specific to Debian GNU/Linux. These are noted in the text. RPM-based system equivalents are provided where known.

You can usually kill an X session with the key combination <ctrl><alt><backspace>. For a managed (xdm, gdm, wdm, kdm, etc.) X session, this usually just restarts the session manager, which can be spectacular, but isn't particularly useful.

You can usually switch to an alternate virtual console, VC, sometimes called a virtual terminal, VT. Preferably one with a command-line login prompt. Use the key combination <ctrl><alt>F[1-6] -- where F[1-6] represents any of the function keys numbered F1-F6 (from X, either left or right <alt> key works, at console, you must use <left alt>). A default Debian GNU/Linux installation runs a getty (terminal login) on the first six VCs. You can also use the chvt command, though this assumes a command line, which you didn't have in the first place, eh? Note that you can issue chvt command remotely, in the event your console is hosed, but your system is still responsive, and you have network access to the machine.

Magic Sysrq

If neither of the above work, and you have compiled it into your kernel, the magic-sysrq key combinations may at least allow you to cleanly shut down your system. Documentation for this is in



Issuing these in sequence (r k e i s u b) should cleanly shut down your system. Note that you may never regain console display, though sometimes issuing commands (for me, usually a console login followed by attempting to mount a floppy) should give some indication of whether or not the system is responsive.

You don't want to run an XDM login session?

The following commands are largely Debian GNU/Linux specific. Where RPM system equivalents are known, they're given.

To disable xdm for the current system session:

$ /etc/init.d/xdm stop


These systems usually launch the X display manager from inittab, meaning you've got to change your runlevel. Typically init 2 is non-X and init 3 is the default, X-enabled, runlevel. I think.

To disable xdm startups for *all* system sessions:

$ /usr/bin/update-rc.d -f xdm remove

Under RPM systems, use the chkconfig utility. man chkconfig for more info.

To allow remote xdm control but disable local control: comment out the localhost display in /etc/X11/xdm/Xservers, e.g.:

$ mv /etc/X11/xdm/Xservers /etc/X11/xdm/Xservers.bak &&
sed -e '/^[ ]*:[0-9] local/s/^/# /' < /etc/X11/xdm/Xservers.bak \ > /etc/X11/xdm/Xservers

Under RPM: Not sure. I'd appreciate the heads up on where this is located, but you'll likely find it under /etc/X11/ someplace.

To remove xdm from your system:

$ apt-get remove xdm

$ rpm -e xdm

Managing X overall has gotten a lot better, and I now typically do run a display manager (partial toward WDM and KDM myself) on systems. However, they still can cause problems, including:

Yes, you can run an X display manager such as XDM, GDM, KDM, WDM, etc., and many people do. You've got the option not to, though.

An alternative X startup method is:

$ startx -- :1 1>.startx.log 2>&1 & exit

RPM: This may or may not work on your system, depending on how the X startup scripts are parsed. I'd appreciate feedback from a current RPM-based system user.

...executed from a console login. This startx X (on display :1 rather than :0 -- if I do want to run an X display, it won't interfere), logs all X server output to the file .startx.log, including error output (useful for diagnosing problems), and exits the console session. It's generally a good idea not to leave unattended console logins on any system to which others may have access. There's a strong tendency to forget about them.

mail: kmself@ix.netcom.com
Last updated 2005/04/08 10:28:39