Question

in linux suppose proccess is down .

how to check it up and know whether the process is running or not running ?

and if process is not running or in down state then how to start that particular process which is not working ??

please tell how to activate or start the particular process is not in working state?

please write the commands and execute and explain the process.

Answer 1

To display Linux processes use
ps (ps command lists running processes )
ps -A(shows all processes)
Or
Enter on terminal - top (running processes)
if u want kill any process then use command ie. kill PId(process id which shows in left side of terminal of top command)


example--
command---->ps -A | grep firefox
 4980 ?        00:00:00 firefox
4950 is the PID
so use kill 4950 (for kill process)

and for start firefox just type firefox and it will be start or for any process u can do same thing Name of process and enter or restart same as above.

some more commands on process 
ps - report a snapshot of the current processes.

      To see every process on the system using standard syntax:
          ps -e
          ps -ef
          ps -eF
          ps -ely

       To see every process on the system using BSD syntax:
          ps ax
          ps axu

       To print a process tree:
          ps -ejH
          ps axjf
       To see every process running as root (real & effective ID) in user format:
          ps -U root -u root u