Gfilui

I'm trying to follow some instructions on getting specific software to open up on a specific monitor. I have three monitors. xrandr -q output is as follows:

Screen 0: minimum 8 x 8, current 5040 x 1080, maximum 32767 x 32767
DVI-D-0 connected 1440x900+3600+79 (normal left inverted right x axis y axis) 408mm x 255mm
 1440x900 59.89*+ 74.98 
 1280x1024 75.02 60.02 
 1280x800 59.81 
 1152x864 75.00 
 1024x768 75.03 70.07 60.00 
 800x600 75.00 72.19 60.32 56.25 
 640x480 75.00 72.81 59.94 
HDMI-0 connected primary 1920x1080+1680+0 (normal left inverted right x axis y axis) 521mm x 293mm
 1920x1080 60.00*+ 59.94 50.00 60.00 50.04 
 1680x1050 59.95 
 1440x900 59.89 
 1440x576 50.00 
 1440x480 59.94 
 1280x1024 75.02 60.02 
 1280x960 60.00 
 1280x720 60.00 59.94 50.00 
 1152x864 75.00 
 1024x768 75.03 70.07 60.00 
 800x600 75.00 72.19 60.32 56.25 
 720x576 50.00 
 720x480 59.94 
 640x480 75.00 72.81 59.94 59.93 
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 connected 1680x1050+0+0 (normal left inverted right x axis y axis) 433mm x 271mm
 1680x1050 59.88*+ 59.95 
 1280x1024 75.02 60.02 
 1280x960 60.00 
 1152x864 75.00 
 1024x768 75.03 70.07 60.00 
 800x600 75.00 60.32 
 640x480 75.00 59.94 
 640x350 70.07 
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)

I'm running 18.04, using Xorg for display, and nVidia 396.

I've tried prepending DISPLAY=":0", or DISPLAY=":0.0", with numerical variations between 0 to 3 for each type. Each time, I get either this message:

Unable to init server: Could not connect: Connection refused
# Failed to parse arguments: Cannot open display:

Or this one:

# Error creating terminal: Failed to get screen from object path /org/gnome/Terminal/screen/47543056_45c7_42eb_8d4e_1277fad5286e

I've also tried using the --geometry option. I thought perhaps adding the following option would open what I need in the left monitor:

--geometry=1680x1050+0+0

However, this just opens up the relevant software maximised in the primary (centre) monitor. Even after trying varying resolutions and offsets, the result would still be the same.

This is really only a minor inconvenience for me, so I don't want to install any additional packages if that's the only way around this, but if I'm using the wrong commands, let me know what I should be using instead.

Essentially, I want to open two terminals. One on my left and right monitors in full screen. To that extent, the base command I use is:

gnome-terminal --full-screen

You were on the right track. The --full-screen option will open the terminal window in full screen mode on the monitor it is displayed on in the first place. But on which monitor is gnome-terminal displayed? Using the geometry parameter, you can specify width, height, and x/y offset:

gnome-terminal --geometry WidthxHeight+Xoffset+Yoffset

...where the offsets are specified in pixels, but width and height are specified in number of columns and lines, respectively. The window will never span multiple monitors and will be placed on the monitor that would contain the biggest part of the window if it spanned multiple monitors.

In your case, despite 0 offset, you made the window 1680 columns wide, which is why it was placed on the middle monitor.

When you want to display the terminal in full screen anyways, use the smallest possible dimensions to ensure that it is placed on the correct monitor in the first place:

#left monitor:
gnome-terminal --geometry 1x1+0+0 --full-screen

#right monitor:
gnome-terminal --geometry 1x1+3600+0 --full-screen