I dealt with this problem recently.
I have three computers - a PC, a Mac and an SGI - all sharing one monitor right now. I have to unplug stuff to change compute - PITA. Anyway I wanted them to all show the same 'standard PC' 2.2 gamma.
The PC was easiest - I put the monitor on "sRGB" mode and left it at defaults. I used color calibration guides to confirm I was getting a result 2.2 gamma. That's in both Windows and Linux.
The Mac was almost the same - I just went through the calibration utility to confirm the monitor's natural gamma and etc. and have Mac set it to 2.2 instead of 1.8.
The SGI was the trickiest for one main reason that everything was way brighter - the blackpoint was way too high when I had sRGB mode. So when I hook up the SGI, I turn the sRGB mode off, and turn the brightness all the way down
and the contrast all the way up
getting the black point and white point to good spots.
Then I just used a gamma calibration guide (the simple thing with the grey and the black+white alternating lines) to tweak it to 2.2 gamma.
I think the setting I used was "gamma 0.875" or something in that area to set it permanently.
Before I did this, whenever I'd draw something on the SGI darks would be way darker and invisible on normal computers but now it all looks fantastical.
I did this
beforehand and when I saw it on a PC everything in the background was black except the lava - but that seems to be the corrected version I uploaded there. I later did the next page
on the SGI with the gamma and everything set and it looked totally right on the Mac and PC the first try - I didn't have to load up Gimp and change the curve.