On Tue, Oct 23, 2018 at 03:09:05PM +0200, Steve Keller wrote: > Of course the file uids/gids have to be changed too, but that's easy > (in single user mode, when no daemons are running using these IDs). > The question is whether Debian expects certain users/groups to have a > fixed value or if I am allowed to change them.
The mapping from username to UID is variable. Two different Debian systems may map the same username differently, depending on which packages were installed in which order. But you have been asking about changing a user name, because you don't like the (length of the) names Debian maintainers have chosen. This is not going to work the way you want. Those user names are hard-coded in many places, from the *.postinst scripts that (re)create the users, to the systemd unit files that launch services as those users, etc.
