Running ps aux just gave me the following output:
...
www-data 26254 0.0 0.7 27304 3544 ? S 15:07 0:00 /usr/sbin/apache2 -k start
1001 25807 0.8 0.8 48444 4332 ? Sl Sep03 1330:24 ./ts3server_linux_x86
...
www-data is the apach2 user. That's okay, it's what I expected with -u, but what is 1001?
Best Answer
It means that user id is 1001 but that id has no name assigned. This can happen for example a command running in a chroot with a user defined in that chroot will not necessarily have a name assigned outside the chroot.