How do you use htop in Linux?

This article provides a quick overview of the htop command-line utility for Linux. We will explore what this interactive process viewer does, why many system administrators prefer it over the traditional top command, how to install it, and the basic keyboard shortcuts needed to monitor your system’s resources effectively.

Understanding the htop Command

htop is a popular, interactive text-mode process viewer for Linux systems. While most Linux distributions come pre-packaged with the standard top utility, htop offers a more user-friendly, colorful, and highly readable interface. It allows users to monitor vital system metrics—such as CPU usage, memory consumption, swap space, and active processes—in real time.

One of the primary advantages of htop is its ability to let you scroll both vertically to view the full process list and horizontally to see complete command lines. Furthermore, you do not need to type process numbers to kill a process or change its priority; you can simply use the arrow keys to navigate and interact with the list. For further reading and advanced configurations, you can explore this excellent htop resource.

Installing htop

Because htop is not always installed by default, you may need to add it using your distribution’s package manager.

• Debian/Ubuntu-based systems: Open your terminal and run sudo apt install htop.
• Red Hat/CentOS/Fedora-based systems: Use sudo dnf install htop or sudo yum install htop.
• Arch Linux: Run sudo pacman -S htop.

Once the installation is complete, you can launch the tool simply by typing htop in your terminal and pressing Enter.

Navigating the Interface

When you open htop, the interface is divided into three main sections:

1. Header: Displays graphical meters for CPU, Memory (RAM), and Swap usage. It also shows general system information like load average, uptime, and the total number of running tasks.
2. Body: Contains the detailed, sortable list of all running processes.
3. Footer: Shows a menu of htop commands and their corresponding function keys.

Essential Keyboard Shortcuts

htop is entirely keyboard-driven, making it highly efficient. Here are some of the most important keys to know:

• Arrows: Scroll through the process list.
• F3 (Search): Type a process name to quickly locate it.
• F4 (Filter): Show only processes that match a specific keyword.
• F5 (Tree View): Toggle between a standard list and a hierarchical tree view, showing parent and child processes.
• F6 (Sort): Change the column used to sort the processes (e.g., by CPU% or MEM%).
• F9 (Kill): Send a termination signal to the currently highlighted process.
• F10 or q: Quit the application and return to the standard command prompt.

By mastering these basic commands, you can easily troubleshoot performance bottlenecks and manage system resources straight from the terminal.