CHAPTER 11. Managing Processes

Question 1

Which of the following is not generally considered a type of process? (Choose two.)

a. A shell job
b. A cron job
c. A daemon
d. A thread

Answer 1

B and D.

There are two different types of processes that each request a different management approach. These are shell jobs and daemons. A cron job and a thread are subdivisions of these generic categories.

Question 2

Which of the following can be used to move a job to the background?

a. Press &
b. Press Ctrl-Z and then type bg
c. Press Ctrl-D and then type bg
d. Press Ctrl-Z, followed by &

Answer 2

B. The Ctrl-Z command temporarily freezes a current job, after which the bg command can be used to resume that job in the background.

Question 3

Which key combination enables you to cancel a current interactive shell job?

a. Ctrl-C
b. Ctrl-D
c. Ctrl-Z
d. Ctrl-Break

Answer 3

A.

The Ctrl-C command cancels the current job. Ctrl-D sends the EOF character to the current job, which can result in a stop if this allows the job to complete properly. The difference with Ctrl-C is that the job is canceled with no regard to what it was doing. The Ctrl-Z keystroke freezes the job

Question 4

Which of the following statements are true about threads? (Choose two.)

a. Threads cannot be managed individually by an administrator.
b. Multithreaded processes can make the working of processes more efficient.
c. Threads can be used only on supported platforms.
d. Using multiple processes is more efficient, in general, than using multiple threads.

Answer 4

A and B.

Individual threads cannot be managed by an administrator. Using threads makes working in a multi-CPU environment more efficient because one process cannot be running on multiple CPUs simultaneously, unless the process is using threads.

Question 5

Which of the following commands is most appropriate if you’re looking for detailed information about the command and how it was started?

a. ps ef
b. ps aux
c. ps
d. ps fax

Answer 5

A.

The ps ef command shows all processes, including the exact command that was used to start them.

Question 6

Of the following nice values, which will increase the priority of the selected process?

a. 100
b. 20
c. -19
d. -100

Answer 6

C.

To increase process priority, you need a negative nice value. -20 is the lowest value that can be used.

Question 7

Which of the following shows correct syntax to change the priority for the current process with PID 1234?

a. nice -n 5 1234
b. renice 5 1234
c. renice 5 -p 1234
d. nice 5 -p 1234

Answer 7

C.

Use the renice command to change priority for currently running processes. To refer to the process you want to renice, use the -p option.

Question 8

Which of the following commands cannot be used to send signals to processes?

a. kill
b. mkill
c. pkill
d. killall

Answer 8

B.

mkill is not a current command to send signals to processes.

Question 9

Which of the following commands would you use from top to change the priority of a process?

a. r
b. n
c. c
d. k

Answer 9

A.

To change the process priority from top, use r for renice.

Question 10

Which of the following commands will set the current performance profile to powersave?

a. tuneadm profile set powersave
b. tuned-adm profile powersave
c. tuneadm profile –set powersave
d. tuned-adm profile –set powersave

Answer 10

B.

To set the tuned performance profile, use tuned-adm profile, followed by the name of the profile you want to set.

Question 11

What is a unit?

Answer 11

A unit is a thing that is started by systemd. There are different types of units, such as services, mounts, sockets, and many more.

Question 12

Which command should you use to show all service units that are currently loaded?

Answer 12

Use systemctl list-units to show all service units that are currently loaded.

Question 13

How do you create a want for a service?

Answer 13

You create a want for a service by using the systemctl enable command.

Question 14

How do you change the default editor for systemctl?

Answer 14

Set the SYSTEMD_EDITOR variable in /etc/profile to change the default editor for systemctl.

Question 15

Which directory contains custom Systemd unit files?

Answer 15

/etc/systemd/system/ contains custom systemd unit files.

Question 16

What should you include to ensure that a unit file will automatically load another unit file?

Answer 16

Include “Requires” to ensure that a unit file will automatically load another unit file.

Question 17

Which command will show available configuration options for the httpd.service unit?

Answer 17

“systemctl show httpd” shows available configuration options for the httpd.service unit.

Question 18

Which command shows all dependencies for a specific unit?

Answer 18

“systemctl list-dependencies –reverse” shows all dependencies for a specific unit.

Question 19

What does it mean if “systemctl status” shows that a unit is dead?

Answer 19

systemctl status output indicating that a unit is dead is nothing serious; it simply means the service is currently not running.

Question 20

How do you create a Systemd override file?

Answer 20

Using “systemctl edit” on the unit that you want to modify creates a systemd override file.