On my high resolution screen for some applications that don't scale to the global scale factor I use a special start-up script, that changes the resolution and scale factor down to Full-HD and scale factor 1 but then the extension that scales everything twice in firefox is making everything really big. I have to disable the extension in the add-on menu by hand.

Is there a way to disable an extension inside a running instance of Firefox from the console?

Or can I alter my add-on Zoom Menu Elements so it stores the zoom state in the file system where I can alter it via bash?

related topic: Fix scaling of java-based applications for a high DPI screen

  • Do you mean the Firefox console?
    – Lucio
    Nov 23, 2014 at 22:35
  • 1
    I mean from bash
    – rubo77
    Nov 23, 2014 at 22:36

1 Answer 1


No there isn't anything elegant... Don't take my word for it, examine the Mozilla remote commands source code

There is a very unelegant method though: pkill firefox&&sleep 1&&firefox -safe-mode.

A bit more detail on the inelegant solution now you mentioned the "Zoom Menu Elements":

There is a way of locking preferences in Firefox, but that is again for a deployment situation, so changing it on the fly is again a pkill firefox&&ChangeUserPref.sh layout.css.devPixelsPerPx iOneorTwo&&firefox.

If this is an option for a solution, a prefs.js file must be created, ChangeUserPref.sh must be written and the "Zoom Menu Elements" must be deactivated (as this functionality will now be managed outside Firefox)

On the "loosing the tabs" because of the restart: that is also a preference, so can be locked as well, but that's the best I can do for you... :(

  • "crude" = "primitiv"
    – Fabby
    Nov 24, 2014 at 2:41
  • Edited my answer to be more clear! Bitte! ;)
    – Fabby
    Nov 24, 2014 at 2:46
  • Maybe something with wmctrl?
    – rubo77
    Nov 24, 2014 at 2:51
  • Restarting ff would be no solution in this case cause you would lose all open tabs. I rather search for a real hacky solution. Maybe a plugin that allows you to control ff from the outside or such
    – rubo77
    Nov 24, 2014 at 6:41
  • I added another idea to my question: alter the zoom addon
    – rubo77
    Nov 24, 2014 at 7:09

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