-Move to /opt
External programs like LibreOffice, Google Chrome, the defunct Adobe reader, ... are all installed in the /opt directory. If you want more info about why /opt, check out these two links:
Where to install my products on linux?
Filesystem Hierarchy Standard
If you already had a previous Firefox version installed in the /opt directory, remove it with the following command:
sudo rm -r /opt/firefox
Now move the firefox directory (which was created in your Downloads folder during extraction) to /opt:
sudo mv firefox /opt/firefox35
-Set up symbolic links
Depending on you usage pattern, follow the instructions you want to use Firefox 35 as you default browser:
“Backup” the old Firefox launcher:
sudo mv /usr/bin/firefox /usr/bin/firefox-old
Create a symbolic link pointing to the new Firefox version:
sudo ln -s /opt/firefox35/firefox /usr/bin/firefox
No need to update your icons/shortcuts, they should now launch the new version of Firefox.
Your old Firefox version is still installed. If you want to use it, run firefox-old in a terminal or create shortcuts/icons referring to firefox-old.
