Process States

What are the process states in Linux?

The following are the process states:

1. Running: This is a state where a process is either in running or ready to run.
2. Interruptible: This state is a blocked state of a process which waits for an event or a signal from another process
3. Uninterruptible: It is also a blocked state. The process is forced to halt for certain condition that a hardware status has waited and a signal could not be handled.
4. Stopped: Once the process is completed, this state occurs. This process can be restarted
5. Zombie: In this state, the process will be terminated and the information will still be available in the process table.

What is a zombie?

Zombie is a process state when the child dies before the parent process. In this case the structural information of the process is still in the process table. Since this process is not alive, it cannot react to signals. Zombie state can finish when the parent dies. All resources of the zombie state process are cleared by the kernel

Check with the command top the different process states

you go to top command to check the running process and the memory they take

This is with top command

This will be with htop command, and wee see more details, a nicer interface to manage processes and we can choose an Function key option as well or we can highlight a specific process

As you could see we can highlight the process and adjust the priority with the F7 ad F8 key (+ or - )

Now we will press F9 and this will be the result

And we want to kill a process , for example Firefox (we checked the process ID PID )

You can close it nicely with F15 , the default one, or you can close it immediately with F9 in a hard way

We can run the Nice command to establish the priority of certain process

This is an example of how to use it. The higher the number, the lower the priority. In this case, very low priority

Linux priority goes for -20 to 19

Now check this example:

I this case it will run with an extra high priority, and your computer will feel that it slow down because all CPU power goes basically to this task.

We can use 15 for a process that is not time critical like backups. You don't use it with customer related issues. In other words, you use it when you want to be nice with other processes
😁

For example, here we can see here a process with a higher priority than the rest of the process -11. The rest has priority "0" the default one.
We need to identify it when we are monitoring the process in your computer