Userdel command , Need explaination
 

hello,

I have the list of users in my /etc/passwd and i being a super admin feel that some of the users need has to be deleted from the list.
Let's say these are following list of users ,

root:$1$FEoFUC9F$QL.JdIPi7Vt7hTsn9htej/:0:0:root:/root:/bin/bash
bin:*:1:1:bin:/bin:/bin/sh
daemon:*:2:2:daemon:/usr/sbin:/bin/sh
sys:*:3:3:sys:/dev:/bin/sh
adm:*:4:4:adm:/var/adm:/bin/sh
lp:*:5:7:lp:/var/spool/lpd:/bin/sh
sync:*:6:8:sync:/bin:/bin/sync
shutdown:*:7:9:shutdown:/sbin:/sbin/shutdown
halt:*:8:10:halt:/sbin:/sbin/halt
mail:*:9:11:mail:/var/mail:/bin/sh
news:*:10:12:news:/var/spool/news:/bin/sh
uucp:*:11:13:uucp:/var/spool/uucp:/bin/sh
operator:*:12:0:operator:/root:/bin/sh
games:*:13:60:games:/usr/games:/bin/sh
ftp:*:15:14:ftp:/var/ftp:/bin/sh
man:*:16:20:man:/var/cache/man:/bin/sh
www:*:17:18:www-data:/var/www:/bin/sh
sshd:*:18:19:sshd:/var/run/sshd:/bin/sh
proxy:*:19:21:proxy:/bin:/bin/sh
telnetd:*:20:22:proxy:/bin:/bin/sh
backup:*:34:34:backup:/var/backups:/bin/sh
ais:*:101:101:ais:/var/run/ais:/bin/sh
nobody:*:65534:65534:nobody:/nonexistent:/bin/sh

from the above list the only that seems valid to me is root, and i guess i can go and delete others...

So before me deleting those users, I just want to know what will be consequences for e.g if i userdel man , does that mean that man will not work...

Can someone explain me above the internals of adding users and deleting them, Is there a uid associated with it etc.. ?

Anyone please throw some light on this ???

~Srihari.

Why do you want to delete any of those users? What problem are you trying to solve?

If you do a Google search using "/etc/passwd linux", you'll find several good links.

These users are system users which are created for privilege separation. That way, if you run an apache server for example, it will run as user www instead of as root. You don't want to delete them.

If I were you, I'd leave things as they are. Deleting those system users may result in some applications, services and daemons not working as expected. As for user management, take a look at this article.

@ all,

Thanks for all your inputs .. I guess each one of you gave me some idea how important these users are.. So going forward i now know what needs to be done with users.

Thanks once again..

~Srihari.