xrandr

ma3@ma3-M68M-S2P:~$ cvt

usage: cvt [-v|--verbose] [-r|--reduced] X Y [refresh]

-v|--verbose : Warn about CVT standard adherance.
-r|--reduced : Create a mode with reduced blanking (default: normal blanking).
X : Desired horizontal resolution (multiple of 8, required).
Y : Desired vertical resolution (required).
refresh : Desired refresh rate (default: 60.0Hz).

Calculates VESA CVT (Coordinated Video Timing) modelines for use with X.
ma3@ma3-M68M-S2P:~$ xrandr
Screen 0: minimum 320 x 200, current 1440 x 900, maximum 4096 x 4096
VGA-1 connected primary 1440x900+0+0 (normal left inverted right x axis y axis) 410mm x 256mm
1440x900 59.9*+ 75.0
1280x1024 75.0 60.0
1280x960 60.0
1152x864 75.0
1024x768 75.1 70.1 60.0
832x624 74.6
800x600 72.2 75.0 60.3 56.2
640x480 72.8 75.0 66.7 60.0
720x400 70.1