Determine if x is running

[Karl Pearson]

On Tue, February 10, 2009 11:30 am, Rick Stevens wrote:
> Karl Pearson wrote:
>> On Mon, February 9, 2009 3:25 pm, Ray Van Dolson wrote:
>>> On Mon, Feb 09, 2009 at 02:21:24PM -0800, redhat at buglecreek.com
>>> wrote:
>>>> I'm am writing a script that sets some various security settings on
>>>> Redhat Boxes.  I would like to try to determine if a gui may be
>>>> running
>>>> on the box the script is run on.  If so, I would echo some
>>>> additional
>>>> text to stdout that instructs the user that they may required to
>>>> manually perform some additional settings manually.  Things having
>>>> to
>>>> do
>>>> with screen savers.  Anyway, I thought about the following:
>>>>
>>>> 1. use the runlevel command or who -r to see if the system is in
>>>> runlevel 5.  This seems flawed since the box may have been started
>>>> in
>>>> runlevel 3 and the startx command may have been used. The commands
>>>> would
>>>> show runlevel 3.
>>>> 2. Check if the environment variable DISPLAY is set.  If so, seems
>>>> like
>>>> there is a good chance that they are running a gui. (maybe)
>>
>> DISPLAY is set by the user's login process, so it would be empty for a
>> cron job.
>>
>>>> Is there a better way to check this that anyone can think of?
>>> Would it be sufficient for your needs to check is the X process is
>>> running?
>>>
>>> Theoretically, there is probably some way to interact with a running
>>> X
>>> server directly from a script (even if you're not in control of its
>>> terminal) to determine if it's running.
>
> The easiest way is a small shell script:
>
> 	#!/bin/bash
> 	RES=`ps ax | grep -v grep | grep -i xorg`
> 	if [ $? -eq 0 ]; then
> 		echo X is running
> 	else
> 		echo X is NOT running
> 	fi
>
> (substitute the name of your X server for "xorg" if you're not running
> XOrg).  On top of that, $RES will be empty if X isn't running, and will
> contain the line from "ps ax" describing it if X is running.
>
> This should work regardless of if the machine starts X by going into run
> level 5 and firing up a greeter or startx from some other run level.  It
> looks for the instance of the X server itself.
>
>>> Also, X typically listens on port 6000 locally.
>
> Not unless you TELL it to.  It will listen on local Unix domain ports,
> but not TCP/IP.
>
>> Just run runlevel and it will return what runlevel is currently being
>> run in the second response, i.e: on boot, it will show N 5 or N 3 for
>> X
>> or text depending on what's in /etc/inittab on the initdefault line.
>>
>> Now then, that doesn't handle startx, but how many times might that
>> actually happen. On my servers, there's no CRT/LCD, so no user will be
>> running startx. They might run vncserver, however, and use an X
>> display
>> remotely. But, they better not leave it in that state, else that will
>> be
>> disabled for them. All the users in my network have Linux PCs anyway,
>> and have no reason to be on the server unless they are editing a web
>> page, but then they can use fish:// in Konqueror or sftp:/// in
>> Nautilus.
>>
>> I suspect I've confused more than helped, but ask away and someone
>> smarter than me will respond.
>
> The shell snippet I provided

HA! I knew you thought you were smarter than me! I knew you were too, by
the way... :)

> ----------------------------------------------------------------------
> - Rick Stevens, Systems Engineer                      ricks at nerd.com -
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---
Karl Pearson
Karlp at ourldsfamily.com
Owner/Administrator of the sites at
http://ourldsfamily.com
---
"To mess up your Linux PC, you have to really work at it;
 to mess up a microsoft PC you just have to work on it."
---