processes

We can use the friendly ps command to provide a list of the running processes as our user's session and some additional information.

To see the processes run by other users and those that don't run from a session (i.e. system processes), we need to provide aux to the ps command like so: ps aux

Another very useful command is the top command; top gives you real-time statistics about the processes running on your system instead of a one-time view.(refreshes every 10 seconds or when you use the arrow keys to browse the various rows).

kill command ends a process. you can provide arguments to determine how rough should the killing be done.

• SIGTERM - Kill the process, but allow it to do some cleanup tasks beforehand

• SIGKILL - Kill the process - doesn't do any cleanup after the fact

• SIGSTOP - Stop/suspend a process

the default is SIGTERM.

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systemctl [option] [service] starts a process/service.

options are:

• Start (now)

• Stop (now)

• Enable (on boot)

• Disable (on boot)

e.g. systemctl start apache2

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also we have Ctrl + Z to pause a process that is blocking the terminal. and adding it to jobs.

now with bg and fg we can decide to continue its running in the back-ground or fore-ground.

also command --arg [blah]& makes the command to run in the back-gorund and also adding it to jobs.

you can see them jobs with the jobs command.

also you can kill them with kill %x command where x is the number of that job in the job list.