Creating shortcuts to run applications conditionally

Question

I was wondering if it is possible to create a keyboard shortcut to run application if it is not yet running in Ubuntu?

This is a valid example for something like a browser which is normally heavily used, and you wouldn't really want to run another instance of it if there is one running already (rather just activate the window).

score 4 · Accepted Answer · edited Apr 13 '17 at 12:25

Save the following script to your home folder as launch_chrome.py:

#!/usr/bin/env python

import subprocess
import wnck
import gtk
import time


screen = wnck.screen_get_default()
while gtk.events_pending():
    gtk.main_iteration()

window_list = screen.get_windows_stacked()

last_active = None
for window in window_list:
    if window.get_application().get_name() == "Google Chrome":
        last_active = window

if last_active:

    timestamp = int(time.time())
    last_active.activate(timestamp)

else:

    subprocess.Popen("google-chrome")

Make the script executable:
```
chmod +x ~/launch_chrome.py
```
Use the command /home/<YOURUSERNAME>/launch_chrome.py when adding a shortcut.

When this shortcut is activated, it will either:

Launch a new Chrome window if there aren't any already running or,
bring the most recently used Chrome window into focus.

score 3 · Answer 2 · edited Apr 13 '17 at 12:24

In Ubuntu there is a package called run-one that is close to what you ask.

I report the description:

 This utility will run just one instance at a time of some command and
 unique set of arguments (useful for cronjobs, eg).

Regarding the keyboard shortcut, see here How to use a hotkey shortcut to run a launcher?.

Regarding the "if there is one running already, just activate the window", I don't know. Not all applications have a window, they may have zero or more than one window. And even in the case of a single window, I don't know of a simple way to map a process to its window.

Creating shortcuts to run applications conditionally

2 Answers2