Launch torbrowsers on the same host from different users
From Debian bug: https://bugs.debian.org/860297
The problem is not, to run multiple Tor Browsers as the same user, but to run multiple Tor Browsers, each from a different user at the same time on the same machine.
After investigation I found, that this is because of a fixed SOCKSPORT and and fixed CONTROLPORT. But each user needs his own SOCKSPORT and CONTROLPORT.