Also the xrand output can be parsed to display the displays.
cristiano@debiantv:~$ xrandr
Screen 0: minimum 320 x 200, current 3200 x 1080, maximum 8192 x 8192
LVDS1 connected 1280x800+1920+0 (normal left inverted right x axis y axis) 331mm x 207mm
1280x800 60.00+
1024x768 60.00
800x600 60.32 56.25
640x480 59.94
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 160mm x 90mm
1920x1080 60.00+ 50.00 59.94 30.00 25.00 24.00 29.97 23.98
1920x1080i 60.00 50.00 59.94
1280x720 60.00 50.00 59.94
720x576 50.00
720x480 60.00 59.94
640x480 60.00 59.94
TV1 unknown connection (normal left inverted right x axis y axis)
848x480 59.94 +
640x480 59.94 +
1024x768 59.94
800x600 59.94
For video suport, screens must be configurable (when used on old laptops and sutff)
an example is to use only the HDMI port like this:
xrandr --output HDMI1 --auto --same-as LVDS1 or xrandr --output HDMI1 --primary
Check "man xrandr" for more options.
Also the xrand output can be parsed to display the displays.
cristiano@debiantv:~$ xrandr Screen 0: minimum 320 x 200, current 3200 x 1080, maximum 8192 x 8192 LVDS1 connected 1280x800+1920+0 (normal left inverted right x axis y axis) 331mm x 207mm 1280x800 60.00+ 1024x768 60.00
800x600 60.32 56.25
640x480 59.94
VGA1 disconnected (normal left inverted right x axis y axis) HDMI1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 160mm x 90mm 1920x1080 60.00+ 50.00 59.94 30.00 25.00 24.00 29.97 23.98
1920x1080i 60.00 50.00 59.94
1280x720 60.00 50.00 59.94
720x576 50.00
720x480 60.00 59.94
640x480 60.00 59.94
TV1 unknown connection (normal left inverted right x axis y axis) 848x480 59.94 + 640x480 59.94 + 1024x768 59.94
800x600 59.94