Install the Firefox beta as you normally would (with
dpkg), then do the following steps to install Minefield and create a custom shortcut for it (
.tar.bz2 file from the Firefox Nightly Builds site. Extract the files into a directory of your choice (I'll just use
sudo tar xvfj firefox-4.0b9pre.en-US.linux-i686.tar.bz2 -C /opt
Minefield should now be installed in
/opt/firefox. Now, let's create a custom command for it:
sudo tee /usr/bin/minefield <<EOF
...and make the script executable:
sudo chmod a+x /usr/bin/minefield
You should now be able to run the command
minefield to start Minefield.
If you want to uninstall Minefield (when it was installed using the above method), simply do the following:
sudo rm -rf /opt/firefox /usr/bin/minefield
I am not quite sure, but I think Minefield has an auto-update feature (it at least have an updater program, which should be located at
/opt/firefox/updater), so you shouldn't have to worry too much about it.