RHCSA Ch2

Question 1

After clicking ‘e’ in the boot loader, what do you type at the end of the ‘linux’ line to get into the emergency target

Answer 1

systemd.unit=emergency.target

Question 2

After clicking ‘e’ in the boot loader, what do you type at the end of the ‘linux’ line to change root password?

Answer 2

rd.break

Question 3

Root password change step 1

command to remount to sysroot

Answer 3

mount -o remount,rw /sysroot

No space between / and sysroot

Question 4

Root password change step 2

Change root directory to sysroot

Answer 4

chroot /sysroot

Question 5

Root password change step 3

Have SELinux rewrite the security context on all files on the next reboot

Answer 5

touch /.autorelabel

Question 6

see default boot target

Answer 6

systemctl get-default

Question 7

set different boot target

Answer 7

systemctl set-default graphical

systemctl set-default multi-user

Question 8

Look at service unit files

Answer 8

systemctl list-unit-files -at service

• t shows all enabled
• a shows all

Question 9

show list of enable running services

Answer 9

systemctl list-units -at service

Question 10

Show unit file of a particular service

Answer 10

systemctl cat rsyslog

Question 11

Disable a service from ever being able to start

Answer 11

systemctl mask atd

Note* atd is a service

Question 12

manage time and date

Answer 12

timedatectl

Question 13

Create a one time job.

Answer 13

at now +5min

at> type in command here then press ctrl D

Question 14

what is the at service called

Answer 14

atq

Question 15

List at jobs

Answer 15

atq

Question 16

view a specific at job

Answer 16

at -c 1

1 = number of the job

Question 17

cancel at job

Answer 17

atrm 1

Question 18

What is a batch job?

create a batch job

Answer 18

Batch job is a job that will fun when the computer is not busy
> batch
at> command here then Ctrl-D

Question 19

Where are user Cron Jobs stored?

Answer 19

/var/spool/cron/

Question 20

Where are System Cron Jobs stored

Answer 20

/etc/cron.d

Question 21

What is the format of the the following Cron tab?

45 23 * * 6 /home/grant/bin/backup.sh

Answer 21

45 23 * * 6 /home/grant/bin/backup.sh
min hr day Month day of week command
The star in the day/month - will run everyday/every month
hr = military time

Question 22

List all of the cron.d directories - daily, hourly, weekly etc…

Answer 22

ls -d /etc/cron.*

Question 23

What are the tree cron job man pages

Answer 23

man cron - covers the service itself
man crontab - explains crontab command usage
man 5 crontab - command format

Question 24

Cron and at user access/deny files

Answer 24

/etc/at.deny
/etc/cron.deny
/etc/at.allow
/etc/cron.allow
see OneNote for user access table ~At and cron allow/deny table