Logging in to use GUI apps

Introduction

It is possible to use some Linux utilities on Condor via a graphical user interface. For example, a simple text-editor named gedit is useful when writing jobscripts. By running gedit on the Condor login node, any files you load and save will all be on Condor – no need to upload/download those files from your PC or laptop.

In both of the above cases you must first log in to Condor with X11 enabled using the instructions below.

MobaXterm on Windows

Everything is taken care of, you don’t need to do anything extra. Log in to the CSF as usual using:

ssh username@submitter.itservices.manchester.ac.uk

and then you can run GUI apps such as gedit straight away.

Mac OS-X

First install XQuartz on your Mac and reboot it. Then log in to the CSF using:

ssh -X username@submitter.itservices.manchester.ac.uk
     #
     # UPPERcase X (to enable X11 forwarding)

Check that you can run GUI apps by running gedit on the CSF login node.

Linux

No extra installs are usually needed. Simply log in to the CSF using:

ssh -X username@submitter.itservices.manchester.ac.uk
     #
     # UPPERcase X (to enable X11 forwarding)

Check that you can run GUI apps by running gedit on the Condor login node.

Checking that GUI apps will run

Once you have logged in to the CSF using one of the above methods, run the following command on the CSF:

echo $DISPLAY

If everything is OK you should see something like:

localhost:11.0
         #
         # The number at the end can be different

If you get nothing displayed then X11 is NOT enabled and you won’t be able to open GUI windows. Things to check:

• Did you use an UPPERcase X in the command: ssh -X username@submitter.itservices.manchester.ac.uk
• If on Mac, after installing X-Quartz, did X-Quartz start automatically when you ran the ssh command in the terminal window? If not, reboot your Mac and try again.