1.4 Configure and use the appropriate processes and services

Question 1

Systemctl command

Answer 1

Enables control of the systemd init daemon

enable {enable a service on boot}

disable {disable a service on boot}

mask { prevent provided unit file from being enabled or activated}

Question 2

cron daemon

Answer 2

Used to manage scheduled tasks called cronjobs

Question 3

crontab command

Answer 3

can create, view , and delete crontab files

-e{edit}
-l{view crontab for current user}
-r{delete crontab file}
-u{create crontab file for specific user}

Question 4

at command

Answer 4

Schedules a command to run once at a particular time
-m{send mail}
-M{prevent mail from sending}
-f{read a job from a file}
-t{run job at specific time}

Question 5

kill command

Answer 5

sends any specific signal to all processes matching the name specified.
-SIGKILL{kill the process immediately}
-SIGTERM {terminate a process}
-SIGHUP{send to a process when its controlling terminal is closed}

Question 6

top command

Answer 6

Acts as a process management tool that allows for interactive process prioritization, sorting, or termination.

Shift+N{sort by decreasing order of PID}
-M{sort by memory usage}
-P{sort by CPU usage}
-u{display processes belonging to users}
-k{terminate the process specified}

Question 7

ps command

Answer 7

Displays process table. (similar to tasklist).
a{list all user-triggered processes}
-e{list all processes}
-l{long-listing of processes}
-u{list processes along with username and start time}

Question 8

lsof command

Answer 8

Prints a list of all the files currently opened to all active processes.

Question 9

htop command

Answer 9

A newer version of an interactive monitor, process viewer, and process manager.

Question 10

nice command

Answer 10

Runs a command with a different nice value than the default.
-n{increments nice value by an integer}

Question 11

renice command

Answer 11

Alters the scheduling priority of an already running process.
-n{specifies the new nice value for a running process}
-g{alters the nice value of processes in a process group}
-u{alters the nice value of all the processes owned by the user}

Question 12

Zombie process

Answer 12

A process was terminated but not yet released by its parent process so it cannot accept a kill signal.

Question 13

Sleeping process

Answer 13

A process is waiting either to be reactivated by the scheduler or until the resource is available.

Question 14

Stopped process

Answer 14

Process was stopped by a debugger or a kill signal.

Question 15

bg command

Answer 15

bg%{job ID} - pushes a job to the background.

Question 16

fg command

Answer 16

foreground
fg%{job ID} - brings a job to the foreground.

Question 17

jobs command

Answer 17

Lists out all jobs either in the foreground or background.

Question 18

CTRL+Z command

Answer 18

Stops a foreground job and places it in the background.

Question 19

CTRL+C command

Answer 19

Force quits a running program via the command line.

Question 20

CTRL+D command

Answer 20

Logs out of the current user session.

Question 21

pgrep command

Answer 21

Identifies a process based on multiple factors when the exact PID is not known.

Question 22

pkill command

Answer 22

Sends any specified signal to processes based on a matching pattern.

Question 23

pidof command

Answer 23

Finds the process ID of a named running program.