Process Management

• What processes are running on the system?

feri@aries:~$ ps axu

• Display the list of running processes in a tree layout.

feri@aries:~$ pstree

• Which processes are currently running on the system owned by root?

feri@aries:~$ ps axu | grep ^root

• What is the process id of the process named init?

feri@aries:~$ ps axu | grep init

• Log in over another terminal and run the program named mc.

feri@aries:~$ mc

• In the other Putty window, find the process id of this Midnight Commander, then send it a TERM signal! (In the solution, your login name is <username>, the process id read is <PID>).

feri@aries:~$ ps axu | grep ^<username> | grep mc$
feri@aries:~$ kill <PID>

• Terminate all your processes with one command!

feri@aries:~$ slay <username>

• Display the list of running processes by load! Monitor the load of the system continuously!

feri@aries:~$ top

• Find all files with .conf extension on the system and list them in /tmp/find-<username>.txt! Since this takes a long time to run, do the search in the background!

feri@aries:~$ find / -name *.conf >/tmp/find-feri.txt &

• Perform the previous task without displaying error messages!

feri@aries:~$ find / -name *.conf 2>/dev/null >/tmp/find-feri.txt &

• Re-run the previous working with low priority!

feri@aries:~$ nice -n 20 find / -name *.conf 2>/dev/null >/tmp/find-feri.txt &

• Run the previous task at 3:10 every night! (No need to run in background & signal in this case. Don't forget to clear this setting when you are done with the task!)

feri@aries:~$ crontab -e
10 3 * * * nice -n 20 find / -name *.conf >/tmp/find-feri.txt

• Exactly at midnight, write the amount of free space in /tmp/free-<username>.txt!

feri@aries:~$ at 0:0
df >/tmp/free-feri.txt

• Display a list of your scheduled tasks!

feri@aries:~$ atq

• At 10AM, make a copy of the /etc/passwd file to the tmp directory.

feri@aries:~$ at 10:00
cp /etc/passwd /tmp

• Cancel the scheduled task that has been just created. (In the solution, the id of the scheduled task is marked <JOBID>.)

feri@aries:~$ atq
feri@aries:~$ atrm <JOBID>