Your problem: you’re running Ubuntu and your current Firefox 3.0.11 is not offering you the much anticipated, very exciting upgrade to Firefox 3.5.  So you’ve downloaded the firefox-3.5.tar.bz2 file and now you want to know how to install it.

Update: If you’ve already installed Firefox 3.5 and now want to upgrade to Firefox 3.5.1 then check out the instructions of How to Upgrade To Firefox 3.5.1 on Ubuntu below. If you’re upgrading from 3.0.11, then just follow the instructions as is.

I’m running Ubuntu 9.04 Jaunty Jackalope and I”m more of a visual user than a command-line user, so I’m going to tell you the way I did.

Rest assured, doing this you will not lose any bookmarks or settings from your current browser. But backup just in case.

1. If you haven’t yet, download the new Firefox 3.5 from Firefox.com to your desktop
2. Right-click the file (firefox-3.5.tar.bz2) and choose Extract Here
3. You will now have a new folder on your desktop called Firefox. Rename it to Firefox-3.5
4. Open a terminal window (just this once) and type sudo nautilus – this will launch your file browser with root privileges
5. Navigate to File System -> usr -> lib ( /usr/lib/ ) and copy the folder Firefox-3.5 into this directory
6. Open the folder Firefox-3.5 and find the file called Firefox.
7. Right click and Make Link. It creates a file called Link to Firefox
8. Cut and paste this link to File System -> usr -> bin ( /usr/bin/ )
9. There is already a link called Firefox so rename that to Firefox.old (if there isn’t, don’t worry), rename your new Link to Firefox to just Firefox

All done.  Now close down all your current Firefox windows, and restart with the improved Firefox 3.5. Tada!

To upgrade in future

You can use Firefox’s built in Check for Updates function, however, this only works when you run Firefox as root.  I did the upgrade moments ago, but had some trouble, so here’s what should work:

• Open a terminal window and type gksudo firefox;
• This will launch Firefox and the Check for Updates option under the Help menu will be active;
• Choose the option, Firefox will check and install any updates. Close and restart Firefox.

Warning: I ran this process as sudo firefox, which apparently is the wrong way to do it.  If you re-open Firefox and there’s a red bar at the top that says your history and bookmarks are locked because it’s in use by another program, then something went wrong. In this instance, root locked several files in my .mozilla user directory, so I couldn’t use it as a normal user.

To fix it, close Firefox and do this:

• Open a file browser and got to home -> yourusername -> .mozilla -> firefox -> xyz.default (profile folder)
• Leaving it open, open a terminal window and type sudo nautilus, which will open a second file browser, and then navigate to the same folder
• In the first file browser window you will see that some files have a locked icon on them
• In your second file browser you won’t see the locks because in that window you have root privileges. So in that window, right click the files and bestow your username onto the locked files, giving permission back to you as a normal user.
  
• Relaunch Firefox and all should be as it was intended;
• If anybody has a reason/easier way to do this, I’ll be happy to hear from you