I used this technique to run two dropbox daemons at the same time. I have one dropbox for data and a separate one for portable applications I use on a USB stick when I’m forced to use Windows. I run two instances of dropbox on the USB stick already, but wanted to keep a copy of the portableapps dropbox on my Ubuntu machine as well. Keeping the two dropboxen separate means I have more control over when the two data stores are updated.

Run the following command in a terminal:

HOME=$HOME/.dropbox-alt /usr/bin/dropbox start -i

This should start the dropbox installer. In the wizard, you can create a new account or link to an existing one. “.dropbox-alt” is the directory where I want the installer to download the new instance — you can choose a different location for the actual dropbox sync folder during the installation. Note that the .dropbox and .dropbox-dist folders will still be created inside the .dropbox-alt folder, so don’t panic if it looks empty.

I haven’t tried it, but I presume this method should work for as many instances as necessary.

I don’t want my second dropbox to run automatically, so I can start it up when I want it with the same command without the “-i” (which runs the installer):

HOME=$HOME/.dropbox-alt /usr/bin/dropbox start

The dropbox wiki suggests adding this line to /etc/rc.local in order to run the dropbox daemon at startup (replace “username” with the actual user):

su username -c “/home/username/.dropbox-alt/.dropbox-dist/dropboxd &”

UPDATE: I tried the previous command and it doesn’t seem to work. I’m trying this instead:

su username -c “HOME=$HOME/.dropbox-alt /usr/bin/dropbox start”