How to view system processes in linux system

Editor to share with you how the linux system to view the system process, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to understand it!

Introduction to the Linux process:

In linux, each running program is called a process, and each process is assigned an ID number

Each process corresponds to a parent process. This parent process can copy multiple child processes, such as wwwserver

Every process can exist in two ways, foreground and background. The so-called foreground process is what the user can operate on the current screen, while the background process is actually operating. But because of the processes that cannot be seen on the screen, they usually run in the background.

In general, the services of the system exist in the form of background processes. And will be resident in the system until the computer is turned off.

Linux system View system process method:

You can use the ps command. It can display information about the currently running process, including the PID of the process. Both Linux and UNIX support the ps command, which displays information about all running processes. The ps command provides a snapshot of the current process. If you want the status to refresh automatically, you can use the top command.

Ps command

Enter the following ps command to display all running processes:

# ps aux | less

Among them

-A: show all processes

A: displays all processes that include other users in the terminal

X: displays the process without a controlled terminal

Task: view each process in the system.

# ps-A # ps-e

Task: view processes that are not running on root

# ps-U root-u root-N

Task: view the processes run by the user vivek

# ps-u vivek

Top command

The top command provides a dynamic real-time view of the running system. At the command prompt, enter top:

# top

Output:

Figure 1:top command: display Linux task

Press Q to exit and h to help.

Displays a tree view of the process

Pstree displays running processes in a tree. The root node of the tree is pid or init. If a user name is specified, the process tree takes the process owned by the user as the root node.

$pstree

Sample output:

Figure 2:pstree-A tree view showing the process

Task: print the process tree using ps

# ps-ejH# ps axjf

Task: get thread information

Enter the following command:

# ps-eLf# ps axms

Task: get security information

Enter the following command:

# ps-eo euser,ruser,suser,fuser,f,comm,label# ps axZ# ps-eM

Task: save the process snapshot to a file

Enter the following command:

# top-b-N1 > / tmp/process.log

You can also email yourself the results:

# top-b-N1 | mail-s' Process snapshot' you@example.com

Task: find the process

Use the pgrep command. Pgrep can find the currently running processes and list the eligible processes ID. For example, the process ID that displays the firefox:

$pgrep firefox

The following command displays the process with the name sshd and owner root.

$pgrep-u root sshd

Say hello to htop and atop

Htop is an interactive process viewer similar to top, but you can scroll vertically and horizontally to view all processes and their command line. PID is not required for the related operation (killing,renicing) of the process. To install the htop input command:

# apt-get install htop

Or

# yum install htop

At the command prompt, enter htop:

# htop

Sample output:

Figure 3:htop-Interactive Linux / UNIX process viewer

Atop tool

Atop is an interactive monitoring tool for viewing the load of a Linux system. It shows the use of critical hardware resources at the system level (from a performance perspective), such as CPU, memory, hard drives, and networks.

It can also show which process is causing a specific load based on process-level CPU and memory load; if kernel patches have been installed, it can show the hard disk and network load of each process. Enter the following command to start atop:

# atop

Sample output:

The above is all the contents of the article "how to check the process of the linux system". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!