Viewing running processes in Linux systems can be achieved in a variety of ways. 1. Use the ps command to view static process information, such as ps aux can list all processes of all users, and combine -u or grep to filter specific users or processes; 2. Use top to monitor process dynamics in real time, support sorting by CPU or memory, and terminate processes; 3. Install htop to provide a more intuitive graphical interface, support mouse operation and scrolling; 4. Other tips include lsof viewing port occupation, ps combined with sort to view high memory occupation processes, and systemctl viewing service PID. Each method has its own applicable scenarios, and combined use can improve the investigation efficiency.

Viewing running processes in Linux systems is an important means to troubleshoot problems, optimize resources, or understand system status. In fact, there are many methods, and each has its own applicable scenarios.

Use the ps command to view static process information

ps is one of the most basic and most commonly used commands, which can display snapshots of processes in the current terminal session.

For example, run:

 ps aux

This lists all processes for all users, including CPU and memory usage. Several of the key fields:

• USER : The user running the process
• PID : Process ID, used to terminate processes and other operations
• %CPU / %MEM : Percentage of CPU and memory occupied
• COMMAND : Command to start the process

If you only want to see a certain user's process, you can add a pipeline to filter:

 ps -u your_username

Or combine grep to find specific processes:

 ps aux | grep nginx

Use top to monitor process dynamics in real time

If you want to see the process status that is constantly updated, top is more suitable. It provides an interactive interface that displays the resource consumption of each process in real time.

It runs very simple:

 top

After entering, you can see:

• Current system load
• Memory usage
• List of running processes (sorted by CPU by default)

You can sort by CPU by P , sort by M by memory, and exit by q
In addition, press k to enter the PID to terminate a process (use with caution).

Graphical tools: htop is more intuitive and friendly

If you want a more modern and more readable interface, you can install htop . Compared to top , its color distinction is clearer and supports mouse operation and scrolling.

The installation method is generally:

 sudo apt install htop # Debian/Ubuntu
sudo yum install htop # CentOS

run:

 htop

It also supports horizontal scrolling to view full command line parameters, which is very helpful for debugging.

Other tips

• Check which process takes a port:

 lsof -i:8080

• Find out the top 5 processes that consume the most memory:

 ps aux --sort=-%mem | head -n 6

• Check the PID of a service:

 systemctl status sshd

Combining these commands allows you to locate problems more flexibly.

Basically these are the methods. Each method has applicable scenarios, quick viewing of ps , dynamic monitoring top , htop to improve experience, and other commands add details. It is not complicated but easy to ignore that only by mastering the combination of them can we truly exert the power of Linux.

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