Linux creates a process whenever a program is launched, either by the user or Linux. This process contains the information of how the program is running and what’s happening in the process. Whenever you type a command lets say ls Linux starts a process to list out all the files. A process is an instance of a running program.
Linux creates a process id pid for every process launched. Linux monitors all the process using the pid which is unique. Pids may repeat has the possible number is used up. There won’t be any process with the same pid at any point of time.
Most of the time Linux takes care of killing or launching the process. However, sometimes the processes hog the CPU or refuse to launch when needed. The below commands will help manually check the process or even kill them.
|ps||display your currently active processes|
|top||display all running processes|
|kill pid||kill process id pid|
|killall proc||kill all processes named proc *|
|bg||lists stopped or background jobs; resume a
stopped job in the background
|fg||brings the most recent job to foreground|
|fg n||brings job n to the foreground|