Linux offers several tools for managing and monitoring running processes, which are essential for efficient system administration. In this article, we will focus on four fundamental commands: ps, top, htop, and atop, which allow you to gain insight into what is happening in your system.

ps Command

The ps command is a basic tool for displaying information about active processes. Without any arguments, ps typically shows processes running in the current terminal. For a broader overview, you can use a combination of arguments such as -e to display all processes or -f for a detailed listing.

• Basic usage: ps
• Display all processes: ps -e
• Detailed information: ps -ef

top Command

The top command provides a dynamic view of running processes, displaying a range of information including CPU and memory usage. It is an interactive tool that allows users to sort processes by various criteria and monitor how system resources are being utilized in real-time.

• Launch: top
• Once launched, you can use keys for sorting or quitting the command (e.g., q for quit).

htop Command

htop is an advanced alternative to the top command, offering a colorful user interface and better readability. It presents a list of processes with options for sorting and filtering by various parameters. With its interactive interface, managing processes such as terminating them or changing their priority is straightforward.

• Installation (if not installed): sudo apt-get install htop (for Debian/Ubuntu) or sudo yum install htop (for CentOS/RHEL).
• Launch: htop

atop Command

The atop command is an advanced monitoring tool that provides detailed information about system performance, including CPU, memory, disk operations, and network activity. Unlike top and htop, atop can record historical performance data, allowing for the analysis of system performance over time.

• Installation (if not installed): sudo apt-get install atop (for Debian/Ubuntu) or sudo yum install atop (for CentOS/RHEL).
• Launch: atop
• To display historical data: atop -r

The ps, top, htop, and atop commands are invaluable tools for any system administrator or user who wants to better understand what is happening in their Linux system. Each of these commands has its specific uses and advantages, so it is beneficial to familiarize yourself with them and use them according to your current needs.