Ubuntu – Move windows to specific screens using the command line

command linemultiple-monitorswindow-managementwindow-manager

This is similar to Quickly place a window to another screen using only the keyboard , but I want to be able to use the command line (so that all I need to do is to recall the command line from the bash history).

E.g., send

  • all the gnome terminal windows to eDP1,
  • all Emacs windows to VGA1, and
  • all Chrome windows to HDMI1

(and maximize them after moving – but not the crazy F11 way, the normal window-manager-style maximization).

I would like to specify windows by the executable name.

Best Answer

Moving all windows of a specific window class to a specific screen by (screen-) name

The script below will send windows, belonging to a specific WM_CLASS (application), to a specific screen, by the screen's name. How that is done is explained in the script and also further below.

The script assumes the screens are arranged horizontally, and more or less top- aligned (with a difference < 100 PX).

The script

#!/usr/bin/env python3
import subprocess
import sys

# just a helper function, to reduce the amount of code
get = lambda cmd: subprocess.check_output(cmd).decode("utf-8")

# get the data on all currently connected screens, their x-resolution
screendata = [l.split() for l in get(["xrandr"]).splitlines() if " connected" in l]
screendata = sum([[(w[0], s.split("+")[-2]) for s in w if s.count("+") == 2] for w in screendata], [])

def get_class(classname):
    # function to get all windows that belong to a specific window class (application)
    w_list = [l.split()[0] for l in get(["wmctrl", "-l"]).splitlines()]
    return [w for w in w_list if classname in get(["xprop", "-id", w])]

scr = sys.argv[2]

try:
    # determine the left position of the targeted screen (x)
    pos = [sc for sc in screendata if sc[0] == scr][0]
except IndexError:
    # warning if the screen's name is incorrect (does not exist)
    print(scr, "does not exist. Check the screen name")
else:
    for w in get_class(sys.argv[1]):
        # first move and resize the window, to make sure it fits completely inside the targeted screen
        # else the next command will fail...
        subprocess.Popen(["wmctrl", "-ir", w, "-e", "0,"+str(int(pos[1])+100)+",100,300,300"])
        # maximize the window on its new screen
        subprocess.Popen(["xdotool", "windowsize", "-sync", w, "100%", "100%"])

How to use

  1. The script needs both wmctrl and xdotool:

    sudo apt-get install xdotool wmctrl

  2. Copy the script below into an empty file, save it as move_wclass.py

  3. Run it by the command:

    python3 /path/to/move_wclass.py <WM_CLASS> <targeted_screen>

    for example:

    python3 /path/to/move_wclass.py gnome-terminal VGA-1

For the WM_CLASS, you may use part of the WM_CLASS, like in the example. The screen's name needs to be the exact and complete name.

How it is done (the concept)

The explanation is mostly on the concept, not so much on the coding.

In the output of xrandr, for every connected screen, there is a string/line, looking like:

VGA-1 connected 1280x1024+1680+0

This line gives us information on the screen's position and its name, as explained here.

The script lists the information for all screens. When the script is run with the screen and the window class as arguments, it looks up the (x-) position of the screen, looks up all windows (-id's) of a certain class (with the help of wmctrl -l and the output of xprop -id <window_id>.

Subsequently, the script moves all windows, one by one, to a position on the targeted screen (using wmctrl -ir <window_id> -e 0,<x>,<y>,<width>,<height>) and maximizes it (with xdotool windowsize 100% 100%).

Note

The script worked fine on the tests I ran it with. Using wmctrl, and even xdotool, on Unity can have some stubborn peculiarities however that sometimes need to be solved by experiment rather than reasoning. If you might run into exceptions, please mention.

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