Rhel 6 Chapter 9 - System Administration

Front 1

What port(s) does VNC use?

Back 1

5900 up to 5909

Front 2

What is the vnc server configuration file?

Back 2

/etc/sysconfig/vncservers

Front 3

Once you've edited the configuration for the vnc server, what do you need to set up
a user?

Back 3

vncserver command by typing:
vncserver, or vncserver :2 to assign port 5902

Front 4

How do you configure the Gnome VNC client

Back 4

vino-preferences

Front 5

What do you need to install for VNC server and client?

Back 5

vinagre
tigervnc
tigervnc-server

Front 6

How do you configure the firewall for VNC?

Back 6

Either run system-config-firewall
-or- system-config-firewall-tui
Add port 5900 TCP and UDP
Add port 5901 to 5905

Front 7

What is the difference between gzip and bzip2?

Back 7

bzip2 is slightly more efficient with large files, but not so much with small files

Front 8

How do you use gzip or bzip2 to compress and decompress?

Back 8

gzip file.txt
gzip -d file.txt.gz

bzip2 file.txt
bzip -d file.txt.bz2

Front 9

How would you zip up and tar the /home directory in one command using gzip?

Back 9

tar czvf home.tar.gz /home

Front 10

How would you zip up and tar the /home directory in one command using bzip2?

Back 10

tar cjvf home.tar.bz2 /home

Front 11

How would you extract home.tar.bz2?

Back 11

tar xjvf home.tar.bz2

Front 12

How would you extract home.tar.gz?

Back 12

tar xzvf home.tar.gz

Front 13

What is star used for?

Back 13

For archiving files in SELinux, but you have to install it

Front 14

What are ps options?

Back 14

ps u ch11084 -- Only show my user processes

ps aux -- Show all running processes from all users
(x lifts the requirement that the listed process is associated with a terminal)

ps eux -- Includes a long list of environmental variables

Front 15

Which switch will give you the ppid?

Back 15

ps axl

Front 16

What command can you run to see a tree view of processes?

Back 16

pstree

Front 17

When using the ps command, what is the column header showing physical memory used?

Back 17

RSS

Front 18

What does SAR do?

Back 18

Gives you the "System Activity Report" a ten minute interval
of system stats

Front 19

How do you get a detailed SAR report with all sorts of stuff?

Back 19

sar -A

Front 20

How do you control how long log files are kept before rotating?

Back 20

edit the /etc/sysconfig/sysstat file and change HISTORY=7

Front 21

How is system data collected for sar?

Back 21

/etc/cron.d/sysstat

Front 22

What is the difference between cron and at?

Back 22

cron is regularly scheduled and at is one time

Front 23

How do you restrict access to cron?

Back 23

edit /etc/cron.allow and cron.deny
By default, only cron.deny exists which means all users can use cron
If neither file exists, only root can cron
if only cron.allow exists, only those users can cron
if only cron.deny exists, then only those users can't use cron
if both cron.allow and cron.deny exist and have humu, then allow takes precedence

Front 24

What are the numbers for nice and renice?

Back 24

-20 is highest priority 0 is default and 19 is lowest

Front 25

Where can you view the nice level?

Back 25

top or ps -axl

Front 26

What's a quick format for renicing the init from 0 to 19

Back 26

renice 19 1

Front 27

You can kill and renice processes from top

Back 27

Whether from the command line or top, reboot resets

Front 28

What are the kill commands?

Back 28

kill
killall
kill -9 (use pstree to verify there are not other processes first)

Front 29

Where can you find the example cron command?

Back 29

/etc/crontab

Front 30

What are some cron wildcards to:
run a command every 5 minutes
Run every hour from 7-10

Back 30

*/5 * * * *
* 7-10 * * *

Front 31

How does a user edit their own crontab?

Back 31

crontab -e
crontab -l (lists your entries)

Front 32

What directory contains a user's cron jobs?

Back 32

/var/spool/cron/{users name}

Front 33

How do you use at?

Back 33

at now + 1 minute
-or- at 3:00 12/21/12
enter your commands
use ctrl-d to exit

Front 34

How can you check and edit at commands?

Back 34

atq to see scheduled at commands
atrm to remove numbered command

Front 35

How do you list names in cron.allow, cron.deny, at.allow, at.deny?

Back 35

humu
root
pinchy

Front 36

Where do you configure what is logged?

Back 36

/etc/rsyslog.conf

Front 37

Where do you configure the rotation of logs?

Back 37

/etc/logrotate.conf

Front 38

Where do you change logging for the vsftpd service?

Back 38

It controls it's own logging, so you have to configure it at
/etc/vsftpd/vsftpd.conf
It's log is in /var/log/xferlog though