Can't figure out what is setting my $DISPLAY variable to 0

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Can't figure out what is setting my $DISPLAY variable to 0

Hi there,

I've recently encountered problems with starting up MATLAB on OSX 10.6.8.

I've figured out from Mathwork's support, that it's because my $DISPLAY variable is, for some reason unknown to me, set to 0.

I have no idea which application or script is changing my $DISPLAY variable.

Is there any way for me to trace what causes this on my computer, or to disable the script/application to set the varible on start up?

I'm right in the middle of writting my thesis and am highly dependent on MATLAB, so I need to solve this problem ASAP.

Thank you for your help!

MacBook Pro, Mac OS X (10.6.8)

Posted on Feb 15, 2012 9:10 AM

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Answer 1

BobHarris

Level 9

53,009 points

Feb 15, 2012 9:58 AM in response to tunglutti

Look in /tmp for an entry that looks like the following

/tmp/launch-RvQ93B/org.x:0

This should be assigned as your DISPLAY environment variable automatically as you login to the Mac OS X GUI.

For example my DISPLAY environment variable looks like

echo $DISPLAY
/tmp/launch-RvQ93B/org.x:0

If you are remotely connecting to another system and exporting your X11 display back to your Mac, then you should be using something like:

ssh -Y username@remote.system.address
-OR-
ssh -X username@remote.system.address

which will automatically export your DISPLAY variable to the remote system and setup an ssh tunnel for transporting the X11 window back to your Mac.

NOTE: You should never personally set your DISPLAY environment variable on your Mac nor on your remote system as part of your shell initialization scripts (.bash_profile, .bash_login, .bashrc, .profile, .cshrc, .tcshrc, .kshrc, .zshrc, etc...)

Message was edited by: BobHarris

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Answer 2

tunglutti Author

Level 1

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Feb 15, 2012 10:11 AM in response to BobHarris

Thanks for your response BobHarris!

Under my /tmp folder I have multiple directories that looks like what you're describing. they look like this:

"launch-4YX5Rh/Render"

"launch-6cp84s/Listeners"

"launch-bMWCqf//0"

"launchd-139.pMcSDr/sock"

Do you have any ideas on which one it is?

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Answer 3

BobHarris

Level 9

53,009 points

Feb 15, 2012 10:14 AM in response to tunglutti

Should end in

org.x:0

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Answer 4

tunglutti Author

Level 1

0 points

Feb 15, 2012 10:23 AM in response to BobHarris

Okay,

I don't have such a file in that directory. Maybe that is the main problem..?

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Answer 5

etresoft

Level 8

46,098 points

Feb 15, 2012 12:51 PM in response to tunglutti

Run X11 manually and see if it shows up. MATLAB seems to be doing something in a non-standard way that isn't kicking off X11 on demand,

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Answer 6

tunglutti Author

Level 1

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Feb 15, 2012 12:57 PM in response to etresoft

Thanks for your reply etresof,

X11 opens automatically when I try to start MATLAB, so that doesn't seem to be the issue.

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Answer 7

BobHarris

Level 9

53,009 points

Feb 15, 2012 1:03 PM in response to etresoft

In Snow Leopard and Lion, X11 is suppose to be started on demand when someone access the DISPLAY value. The /tmp/launch-0cxGPr/org.x:0 is a Named Socket which launchd is listening to:

lsof /tmp/launch-EcQ2yO/org.x:0
COMMAND PID     USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
launchd 125 raharris   12u  unix 0xffffff80154aafa0      0t0      /tmp/launch-EcQ2yO/org.x:0

If this does not exist, then that would say something is not right on the OP's system.

The OP could always try an lsof search

lsof | grep org.x:0
launchd     125 raharris   12u    unix 0xffffff80154aafa0       0t0         /tmp/launch-EcQ2yO/org.x

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