Managing Processes

When working with Linux, it's essential to know how to manage processes. Processes are running instances of programs on your system, and you need to manage them to ensure that your system runs smoothly. In this section, we'll cover how to manage processes using the command line.

Listing Processes

To list the running processes on your system, you can use the ps command. This command will give you a list of all the processes currently running on your system, along with their process ID (PID), status, and other information.

$ ps -ef 

This will display a list of all processes on your system, including the ones that are running in the background.

Killing Processes

Sometimes you need to stop a process that's causing problems or using up too many resources. You can do this using the kill command. The kill command sends a signal to a running process, telling it to stop.

$ kill <PID> 

You'll need to replace <PID> with the process ID of the process you want to kill. If you want to force the process to stop, you can use the kill -9 command.

$ kill -9 <PID> 

This will force the process to stop immediately.

Managing Processes with top

Another way to manage processes is to use the top command. top shows you a real-time, dynamic view of the processes running on your system. It provides a list of processes and their resource utilization, so you can quickly identify any processes that are using too much CPU or memory.

$ top 

This will display a live view of the processes running on your system. You can sort the processes by various parameters, such as CPU usage or memory usage, by pressing the corresponding key on your keyboard.

Background Processes

Sometimes you want to run a process in the background so that you can continue to use the command line. To do this, you can use the & character.

$ process & 

This will run the process command in the background, allowing you to continue to use the command line. You can view the status of the process using the jobs command.

$ jobs 

This will display a list of all background processes currently running on your system.

Bringing Processes to the Foreground

If you want to bring a background process to the foreground, you can use the fg command.

$ fg %1 

This will bring the process with job ID 1 to the foreground.

Suspending and Resuming Processes

Sometimes you want to suspend a process temporarily, allowing you to run another process. You can do this using the CTRL-Z key combination.

$ CTRL-Z 

This will suspend the currently running process. To resume the process, you can use the fg command.

$ fg 

This will bring the suspended process back to the foreground.

Changing Process Priority

You can also change the priority of a process using the nice command. The nice command allows you to adjust the priority of a process, giving it more or fewer resources.

$ nice <command> 

This will run the <command> with a lower priority, giving other processes more resources. You can also use the renice command to change the priority of an already running process.

$ renice <priority> <PID> 

This will change the priority of the process with the given process ID (<PID>) to the specified priority level