Install Firefox 4 in Ubuntu

Firefox 4 is available for Ubuntu 10.04 and 10.10. To install it use the following commands

sudo add-apt-repository ppa:mozillateam/firefox-stable
sudo apt-get update
sudo apt-get upgrade

This will update your Firefox to version 4. Note that this will not install Firefox 4 side by side with your previous version as used to be the case with beta versions. As this installs the stable release version of Firefox so your previous version will be removed and after installation you will only have Firefox 4.0.

Install Firefox 4 beta (Minefield) on Ubuntu

UPDATE: Firefox 4 (stable version) is now available for Ubuntu. So you can install it instead. Instructions on installing Firefox 4 can be found here

To install Firefox 4 beta on Ubuntu execute following commands

sudo add-apt-repository ppa:ubuntu-mozilla-daily/ppa

sudo apt-get update

sudo apt-get -y install firefox-4.0

The new browser will appear as Minefield 4.0 Web Browser in Applications Menu. It will be installed alongside your existing Firefox install (if any).