4) Basic System Administration

Chapter 18

SAM (system administration menu), sysadmsh

a) Root and superuser

login as root
type "su" and then the password within any user account
type "su username" to login to any account


Why is it not a good idea to always login as root?

b) Start up and shut down the system

single-user mode
inform users before shutdown
wall (write to all)
Command: shutdown


Why is it dangerous to turn the power off without shutting down properly?

c) Managing user accounts

create and delete accounts:
a typical line of the /etc/password file:
upriss:hdj472mfiwv:22101:20:Uta Priss,,,:/Users/upriss:/usr/bin/csh
create home directory for user
copy .login files to user's home directory
assign user to group (/etc/group)
other settings (quota etc.)

user support:
cope with lost passwords
answer hundreds of questions!


What is your own group, user id? Have a look at the /etc/passwd file and the /etc/group file.

d) Regular duties

monitor performance
du -s *|more

file system versus filesystem

back up
tar -cvf /tmp/bkup11.26.97 /Users/upriss
gzip /tmp/bkup11.26.97
tar -rvf /dev/rmt/0m /tmp/bkup11.26.97.gz

check the file system integrity


tar one of your directories into a file, gzip it, then gunzip it and extract it (tar -xvf).

e) Security

last |more

Subscribe to the appropriate mailing lists for updates.

Disable all inet services that are not required (especially rlogin, finger, systat). Install safe versions of the services that are required. The files "hosts.allow" and "hosts.deny".

Check the /etc/passwd file from time to time.


Type "last|more". Have a look at the files in /etc/inet, especially /etc/inet/inetd.conf.

f) Printer service


g) Install hardware and software

Cannot be explained in this class!