Some problem shows as follow when executing IDL/ENVI program in Terminal from remote Linux Server:

% DEVICE: Unable to connect to X Windows display: :0
% DEVICE: Unable to open X Windows display.
Is your DISPLAY environment variable set correctly?

Solution to this problem in step:

ssh to remote server

1 IDL> print,getenv('DISPLAY')

2 IDL> setenv,'DISPLAY=:0.0'

 exit and ssh remote server again:

'ssh -X xxx'

It's OK.

TEST:  IDL>ENVI

reference:

http://www.physics.sfsu.edu/compsys/tutor/idltut/setdisp.html

http://www.mombu.com/programming/idl/t-idl-63-intel-in-mac-idlwave-graphics-crash-1547705.html

https://groups.google.com/forum/#!topic/comp.lang.idl-pvwave/rPfJIAEUhi4