Q:

Cleaning Up Unused Users and Groups (Ubuntu 10.10 Server)

I'm very much a beginner when it comes to Ubuntu and I've been learning the ropes by diving in and writing a (backend-language independent) web app framework that relies on apache, some clever mod_rewrites, Ubuntu permissions, groups, and users. One thing that really annoys my inner clean-freak is that there are loads of users and groups that are created when Ubuntu is installed that are never used (Or so I think). Since I'm just running a simple web app server, I would like to know: What users/groups can I remove?
Since you'll probably ask for it...here's a list of all the users on my box (excluding the ones I know that I need):
root
daemon
bin
sys
sync
man
lp
mail
uucp
proxy
backup
list
irc
gnats
nobody
libuuid
syslog

And a list of all of the groups:
root
daemon
bin
sys
adm
tty
disk
lp
mail
uucp
man
proxy
kmem
dialout
fax
voice
cdrom
floppy
tape
sudo
audio
dip
backup
operator
list
irc
src
gnats
shadow
utmp
video
sasl
plugdev
users
nogroup
libuuid
crontab
syslog
fuse
mlocate
ssl-cert
lpadmin
sambashare
admin

A:

Don't remove any of them.  They are static users that are assumed to exist by software packages, which may break if you change or remove any users.  The users do no harm where they are - they are not "users" in the normal sense.
Se also the Debian Policy Manual - Users and groups, which applies to Ubuntu too.

