Background, Froeground & kill Process in Linux

The ps (i.e., process status) command is used to provide information about the currently running processes, including their process identification numbers (PIDs)

ps Options:

-e  -  Everything, all process

-f  -  Full format listing

-u (username)  -  Display username’s process

-p (PID)  -  Display information for PID

Common ps Command:

ps  -e  -  Display all process

ps  -ef   -  Display all process,Full

ps -eH  -  Display a process tree

ps -e --forest  -  Display a process tree

pstree  -  Display process in tree format

ps -u (username)  -  Display a user’s process

top  -   Interactive process viewer

ps

top

Background Process:

Unlike with a foreground process, the shell does not have to wait for a background process to end before it can run more processes. Within the limit of the amount of memory available, you can enter many background commands one after another

Background & Foreground Process:

command &  -   Start command in background

ctrl+z  -  Suspend the foreground process

bg {num}  -  Background a suspended process

fg {num}  -  Foreground a background process

jobs  -  Lists jobs

Sending Foreground Process to Background:

man ls

crtl+z

bg

 List Background Process: 

jobs

Start Command in Background:

 man ls &

Foreground a Background Process:

fg 1 (job id)

Kill a Running Process:

ctrl+c  -  Kill a foreground process

kill -l  -  Display a list of signal

kill [-sig] [pid]  -  Send a signal to a process

ex:- 1. kill pid = kill -15 pid = kill -Term pid

        2.  kill -9 pid  (-9 for kill signal)

kill -9 2027