I'm hopeing you can help me with this. I've been tasked with transfering some software from I've developed from my linux laptop to a fresh linux install. The fresh install is going to be provided as an ISO to our customers, so we wanted it to be very minimalist with only the programs nessesary to run our software.

Anyways I finished installing everything and try to run my program but I get the complaint that I can't open display. In fact I am told that I can't open display for anything with grapics. I was running as root originally which a google search suggests can cause trouble, but when I su to a regular user I get the same problem.

and a list of things I've tried from google searches: When I try to run xhost +localhost (or any variant) I get the same complaint about opening display. if i do a xauth list localhost.localdomain is the only thing listed. I guess that I should add somethign here but I don't know how.

When I ran the redhat install I intentionally did not install gnome to keep the install as small as possible. I don't explicitly recall selecting any display manager to install, although I may have chosen the defualt for Redhat. It may be that I don't have a display manager installed at all. How would I even determine that?

Anyways any help would be appreciated. I've picked up a few things about linux but I'm still a bit of a newbie, always end up needing help from people smarter then me .

Thank you

"Can't open display" usually means there's no X server running in the system.
Is the X server active in your situation?

I'm actualy not certin. when I do a ps xserver isn't listed; but that is the case even when i run it on the machine i know has an xserver running so i'm guessing the process goes by a differnt name? XFS is running but i'm not certin that is the same thing.

XFS is the filesystem. The X server process will be listed in the output of
ps -e
as just X

You need to start the server before you can use graphics in applications.

your right that was the problem. thank you for the help, I feel a bit stupid I couldn't figure that one out on my own .

actually I still need to do more it seems. I can run startx and everything runs fine but I need everything automated. How do I ensure that the x server is running at startup? preferable with as little overhead as possible. I'm assuming that wouldn't be putting startx in the startup scripts

Also after running the program it turns out the GUI looks horrible, far worse then it does on my development machine. I'm assuming that is due to using XDM, so I suppose I need to use GDM after all. could you tell me what file I would have to modify to use GDM by default?

Thanks in advance