Detect key press combination in Linux with Python?

Question

I'm trying to capture key presses so that when a given combination is pressed I trigger an event.

I've searched around for tips on how to get started and the simplest code snippet I can find is in Python - I grabbed the code below for it from here. However, when I run this from a terminal and hit some keys, after the "Press a key..." statement nothing happens.

Am I being stupid? Can anyone explain why nothing happens, or suggest a better way of achieving this on Linux (any language considered!)?

import Tkinter as tk

def key(event):
    if event.keysym == 'Escape':
        root.destroy()
    print event.char

root = tk.Tk()
print "Press a key (Escape key to exit):"
root.bind_all('<Key>', key)
# don't show the tk window
root.withdraw()
root.mainloop()

Ulf · Accepted Answer · 2009-02-05 13:12:09Z

3

Tk does not seem to get it if you do not display the window. Try:

import Tkinter as tk

def key(event):
    if event.keysym == 'Escape':
        root.destroy()
    print event.char

root = tk.Tk()
print "Press a key (Escape key to exit):"
root.bind_all('<Key>', key)
# don't show the tk window
# root.withdraw()
root.mainloop()

works for me...

answered Feb 5, 2009 at 13:12

Ulf

19.5k5 gold badges21 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Ben L Over a year ago

Hmm, this works - thanks - but I don't really want the window being displayed. I'm aiming to have a background process that sits and waits for the combination.

Ulf Over a year ago

I am sorry, but I do not know how you would achieve that, but at least you have a new direction for further research.

S.Lott · Accepted Answer · 2009-02-05 13:26:15Z

1

What you're doing is reading /dev/tty in "raw" mode.

Normal Linux input is "cooked" -- backspaces and line endings have been handled for you.

To read a device like your keyboard in "raw" mode, you need to make direct Linux API calls to IOCTL.

Look at http://code.activestate.com/recipes/68397/ for some guidance on this. Yes, the recipe is in tcl, but it gives you a hint as to how to proceed.

answered Feb 5, 2009 at 13:26

S.Lott

393k83 gold badges520 silver badges791 bronze badges

Comments

Ben L · Accepted Answer · 2010-01-12 11:14:22Z

1

Alternatively (a non-Python option) use XBindKeys.

answered Jan 12, 2010 at 11:14

Ben L

7,1189 gold badges42 silver badges35 bronze badges

Comments

Sam · Accepted Answer · 2016-01-30 23:19:17Z

1

Well, turns out there is a much simpler answer when using GNOME which doesn't involve any programming at all...

http://www.captain.at/howto-gnome-custom-hotkey-keyboard-shortcut.php

Archived on Wayback

Just create the script/executable to be triggered by the key combination and point the 'keybinding_commands' entry you create in gconf-editor at it.

Why didn't I think of that earlier?

edited Jan 30, 2016 at 23:19

Sam

1,5103 gold badges19 silver badges28 bronze badges

answered Feb 5, 2009 at 14:16

Ben L

7,1189 gold badges42 silver badges35 bronze badges

Comments

Community · Accepted Answer · 2020-07-16 18:41:23Z

0

tkinter 'bind' method only works when tkinter window is active.

If you want binding keystrokes combinations that works in all desktop (global key/mouse binding) you can use bindglobal (install with pip install bindglobal). It works exactly like standard tkinter 'bind'.

Example code:

import bindglobal
def callback(e):
    print("CALLBACK event=" + str(e))

bg = bindglobal.BindGlobal()
bg.gbind("<Menu-1>",callback)
bg.start()

edited Jul 16, 2020 at 18:41

CommunityBot

11 silver badge

answered Nov 22, 2019 at 11:39

segalion

111 bronze badge

Collectives™ on Stack Overflow

Detect key press combination in Linux with Python?

5 Answers 5

2 Comments

Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

2 Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related