I had the same need like you : running many instances of firefox on the same machine.
Basically, when you run an instance of firefox, there is a folder
.mozilla in your
$HOME is created ( if it is not existed yet). You can use the multi-profile solution if you want, as iglvzx mentioned above. So all user's profiles live in that .mozilla directory(database).
I have another trick which I think is more elegant than that solution.
Create a directory to save a new firefox:
$ mkdir $HOME/new_firefox
$ cd $HOME/new_firefox
$ tar xvf setup/firefox-33.0.tar.bz2
Then create a small script like:
$HOME/firefox/firefox -no-remote &
So now run the scrip to have another instance of firefox. And your new user's profile live in
If you use GNOME, just create a
new_firefox.desktop file and put it in
/usr/share/applications directory or in
$HOME/.local/share/applications directory. The
Exec argument in that file is
Exec=/home/your_name/path-to-your-script. If you don't know how to create one, see an existed one in either of 2 above directory.