Firefox Developer Toolbar commands that are useful to all users

Martin Brinkmann
Jul 24, 2015

The Developer Toolbar is a command driven console in the Firefox web browser that enables you to perform specific actions within the browser.

While you may run most of these actions from other locations within the browser as well, it is often faster and more convenient to use than those options.

As far as basics are concerned, you display the Developer Toolbar with the shortcut Shift-F2, or by tapping on the Alt-key and selecting Tools > Web Developer > Developer Toolbar.

It opens as a single line at the bottom of the interface waiting for input. One command that you may want to use first is help, as it lists the commands the Developer Toolbar supports at this point in time.

Developer Tools commands useful to all Firefox users

firefox developer toolbar

We have covered several commands in the past, and since I don't want to rehash information, I merely link to the guides instead.

  1. Take screenshots from the Developer Toolbar
  2. Manage Firefox add-ons from the Developer Toolbar
  3. Change Firefox preferences from the Developer Toolbar
  4. Edit or remove cookies from Firefox's Developer Toolbar

While those are certainly useful, the following commands may prove useful as well:

1. Restart Firefox

firefox restart

Firefox has no native restart button or option but may display a restart dialog when you upgrade the browser or install select add-ons.

To restart from the Developer Toolbar, use the following command:

  1. restart

The command supports two parameters:

  • --nocache to prevent the loading of cached content on startup.
  • --safemode to run Firefox in Safe Mode on restart.

2. Manage and clear the appcache

clear appcache

The application cache is used by HTML5 applications as local storage. It is used for a variety of purposes, for instance to enable offline access to data or improve the loading of resources that are regularly used by a web application.

The following two commands may be useful to all Firefox users:

  • appcache clear to delete entries from the application cache.
  • appcache list to display application cache entries.

3. Open a local folder

open local folder

You can open local folders right from the Developer Toolbar. While this may not be faster than opening them via shortcuts or the local file browser, one supported parameter ensures that you can open the Firefox profile folder quickly.

The support commands are:

  • folder open c:\example to open the example folder on drive c.
  • folder openprofile to open the profile folder of the profile used in the session.

4. Resize the page


You may use the resize command to resize the page in Firefox . This can be useful if you want it to  display in a specific size without having to use the mouse to resize it.

The command to do so is:

  • resize to 1024 800 which resizes the page -- not the browser window -- to a width of 1024 pixels and a height of 800 pixels.

Closing Words

Firefox's Developer Toolbar is a powerful feature of the browser that receives new commands on a regular basis. While most commands are of limited use to non-developers, some may improve how you work with the browser.

Firefox Developer Toolbar commands that are useful to all users
Article Name
Firefox Developer Toolbar commands that are useful to all users
A list of commands supported by Firefox's Developer Toolbar that all users of the browser may find useful.

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  1. Tim said on September 23, 2018 at 10:37 pm

    Ver. ^@ kills this. What next for restart options?

  2. abood said on July 25, 2015 at 4:16 am

    I’ve been using the Restartless Restart add-on ever since it was released.

    Thanks for demonstrating how to do it in a different way.

  3. A different Martin said on July 25, 2015 at 12:37 am

    I never paid any attention to the Developer Toolbar before, but the restart trick alone makes it worth learning about, especially if you use Session Manager with shutdown and startup prompts and want to avoid them when doing a simple restart. (I used to have an extension that added a “Restart” item to the File menu. I think it was the MR Tech Toolkit extension and that it became incompatible with either Firefox/Pale Moon or with one of my critical extensions. I have kind of missed the quick-and-easy restart functionality, but obviously not enough to go searching for an alternative!)

    By the way, the Developer Toolbar can be found in Pale Moon, as well. (Restart works, but I haven’t tried anything else.)

    1. Richard Allen said on July 25, 2015 at 9:39 am

      I couldn’t get them all to work in PM either. ;(

    2. Pants said on July 25, 2015 at 6:36 am
      1. A different Martin said on July 25, 2015 at 8:44 am

        Hey, thanks! I’ve already installed it in both both Pale Moon and Firefox!

  4. greg said on July 24, 2015 at 4:00 pm

    Do you know if there is a way to go directly to the uBlock dashboard from the developer Toolbar? I hate having to use the mouse to click through the icon to get to the dashboard.

    1. Richard Allen said on July 25, 2015 at 8:19 am

      What I do is not from the developer toolbar but I use an addon “Bookmarks menu” v1.91 which replaces the Bookmarks Toolbar with a button, it uses like zero memory if that is a concern. I don’t leave my bookmarks toolbar visible and I’m not aware of a shortcut for just the bookmarks toolbar. I have the uBlock dashboard and Ghostery options bookmarked in the bookmarks toolbar. i have the Menu Bar hidden and put some addon icons (uBlock, YouTube High Definition, YesScript) in there but they don’t all work properly from there for some weird reason unless you click on another icon first like YouTube High Definition, which works fine from the menu bar. And then of course if the Menu Bar is hidden (like mine) the shortcut to see the Menu Bar is the Alt key. Just another option, hoped it helped.

    2. ZzzZombi said on July 24, 2015 at 7:32 pm

      Not really a developer command solution but you could just add “chrome://ublock0/content/dashboard.html” to your bookmarks and give it a short name. And then Ctrl+L – dashboard – enter.

      1. ahs said on July 25, 2015 at 1:29 am

        Good tip. Thanks!

      2. greg said on July 24, 2015 at 10:33 pm


  5. Sören Hentzschel said on July 24, 2015 at 2:18 pm

    The screenshot command has a nice new option in Firefox 42: you can upload the screenshot directly to Just type: screenshot –imgur

    1. Martin Brinkmann said on July 24, 2015 at 2:58 pm

      Now that is nice. Just make sure you don’t show anything you don’t want the Internet to see ;)

      1. dexter86 said on July 24, 2015 at 6:03 pm

        I’m pretty sure it’s only UPLOADED to imgur, not PUBLISHED. So you get the link and can send it to anyone, but it’s not published to

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