Ubuntu: two versions of Firefox at once

Ever since I switched to Linux I’ve been toying with running two versions of Firefox simultaneously, even though I now use Google Chrome as my primary browser.  Why two versions of Firefox, you ask?  It’s kind of complicated, but it boils down to: I use Zotero for my bibliographic management software but I have too many references to put them all in one database.  I have about 10 Zotero databases, and I periodically need to move references from one database to another.  With only one copy of Firefox on my computer, I can only open one copy of Zotero at a time.  And given how you switch between Zotero databases (restarting Firefox), it can be quite cumbersome to move references between databases.  The solution: Two (or more) versions of Firefox, each of which can be opened independently and is compatible with Zotero.

I was getting ready to move some references around today when I thought I’d look into running two versions of Firefox simultaneously just to see what is available.  Turns out, there is a Firefox add-on, specific to Ubuntu, just for this: FoxTester (here’s the extension’s homepage).  Basically how this works is, in the default Firefox install, you install the FoxTester addon.  Then, once you restart, you can right-click in Firefox and you’ll see a context menu:

The top item in the context menu is “Browse FTP Directory.”  This takes you to a repository of Firefox releases, which you can navigate to find the version you want:

Once you find the one you want, click through to the appropriate files for your platform (in my case: 3.6.9/linux-i686/en-US/).  You’re looking for the “tar.bz2” file, which is basically a zip file:

Right click on the tar.bz2 file, and save it to a specific folder (you will probably need to create a folder where you can keep it around as it needs to be static).  Once you’ve downloaded the file to the right folder, go back to your current install of Firefox, right-click again, and go to the context menu for FoxTester.  Select “Preferences” and you’ll get this window:

Here you simply need to set the “Watched Folder” to the folder where you just saved the tar.bz2 file.  Once you’ve done that, you’re two clicks away from running.  Close the Preferences window and right-click to bring back up the context menu.  Assuming you’ve done everything correctly, you should now be able to choose “Install” and select the tar.bz2 file you downloaded.  It will take a minute or two, then you’ll get a note saying that your version of Firefox installed.  You can then go back to the context menu and select “Launch” and choose the version you just installed.  It should start right up:

If you’re doing what I am, which is running two instances of Zotero, you’ll need to download the Zotero extension in the new version, but then you should be good to go.

(Note: The extension’s website has a video tutorial showing this and more.)