What is the difference between DISPLAY :0 and :0.0? On RedHat 5.8, I can right click the desktop to start a shell and DISPLAY will be ":0". If I go to the Menu-System-Terminal to start a shell then DISPLAY will be ":0.0". Can I always assume that these are really the same display?

For example, if I VNC in to a machine on DISPLAY 33, can I assume that ":33.0" and ":33" are the same display with the same permissions?


2 Answers 2


The first number is the Xserver number (port 6000+Xserver_number), the second number is the screen number managed by this server. A single Xserver can manage many screens. If you don't care about screens, empty is the same as 0.


From X(7):

screennumber Some displays share a single keyboard and pointer among two or more monitors. Since each monitor has its own set of windows, each screen is assigned a screen number (beginning at 0) when the X server for that display is started. If the screen number is not given, screen 0 will be used.

I think I can rely on the fact that ":0" is the same as ":0.0".

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