This page describes how to run Mozilla builds of Firefox in Ubuntu. This can be useful if you want to check whether a bug exists in upstream versions of Firefox.

Instructions

Installation

The following instructions will install Firefox in your home directory, and will use a different profile for Mozilla and Ubuntu builds of Firefox.

1. Go to the Firefox download page

2. Download Firefox for Linux

3. Extract the file you downloaded into ~/firefox (e.g. by doing tar jxf firefox*.tar.bz2 -C $HOME)

4. Make a backup of your ~/.mozilla directory (e.g. by doing tar zcPf ~/mozilla-backup-$(date +%s).tar.gz ~/.mozilla)

5. Skip to the end of these instructions unless this is your first time, or you have uninstalled Firefox using the instructions below

6. Run ~/firefox/firefox -ProfileManager to start the Firefox profile manager

7. Create a new profile called mozilla-build

8. Make sure that the default profile is still selected

9. Click exit to close the profile manager (do not start Firefox)

10. Run the following shell script:

    mkdir ~/bin
    cat > ~/bin/firefox <<END
    #!/bin/bash
    
    exec "\$HOME/firefox/firefox" -P mozilla-build "\$@"
    END
    chmod 755 ~/bin/firefox

The firefox command in your ~/bin directory will now run Firefox with the mozilla-build profile.

Uninstallation

1. Delete the ~/firefox directory and the ~/bin/firefox file

2. Run firefox -ProfileManager and delete mozilla-build

Restore your old profile

To restore the backup of your profile, do the following:

1. Close any open Firefox windows

2. Rename ~/.mozilla (e.g. mv ~/.mozilla ~/.mozilla-broken)

3. Extract your archive (e.g. by doing tar zxPf ~/mozilla-backup-DATE.tar.gz

This will completely reset your Firefox profile to the point when you made the backup.

Rationale

There are many ways to run Mozilla builds alongside Ubuntu builds, depending on your needs. This section will discuss some of the choices made in the above instructions.

The guide does not recommend using UbuntuZilla. UbuntuZilla automates the Firefox installation process, but at the time of writing it had not been updated for the latest version of Firefox.

The guide recommends that you back your Mozilla profile up. Regular backups are always recommended, especially before a major software upgrade. Special precaution is necessary here because new versions of Firefox can make backwards-incompatible changes to profiles, and because the Ubuntu Mozilla Team doesn't guarantee profile stability between Ubuntu and Mozilla builds of the same version of Firefox¹.

The guides recommends extracting Firefox into your home directory. This is because extracting to another location (such as /usr/local) would require super-user permissions, without any benefit in the single-user case. If you want to provide new versions of Firefox on a multiple-user system, you are urged to use the recommended procedure. Installing non-Ubuntu software on a multi-user system massively increases your administrative burden - for example, you put your users at risk unless you manually update programs every time there's an update.

The guide recommends that you create a mozilla-build profile for the downloaded version of Firefox. This is partially because of the above-mentioned compatibility issues, and partially because debugging Firefox is much easier with a fresh profile.