I want to change gamma for my first monitor. Every time I invoke xgamma with different -display parameters it somehow points to my second monitor. But I want to modify first one.

I tried these commands.

The parameters I have used for -display are :0, :0.0, :0.1, :1.0, :1.1, :1. Only the first 2 works. But it points to my second monitor. Not the first one. Here is a shell script to test it.

shiplu@KubuntuD:~$ xgamma -display :0
-> Red  1.000, Green  1.000, Blue  1.000
shiplu@KubuntuD:~$ xgamma -display :0.0
-> Red  1.000, Green  1.000, Blue  1.000
shiplu@KubuntuD:~$ xgamma -display :0.1
xgamma:  unable to open display ':0.1'
shiplu@KubuntuD:~$ xgamma -display :1.0
xgamma:  unable to open display ':1.0'
shiplu@KubuntuD:~$ xgamma -display :1.1
xgamma:  unable to open display ':1.1'
shiplu@KubuntuD:~$ xgamma -display :1
xgamma:  unable to open display ':1'

How can I change the gamma for the first/primary monitor?