What is htop command in Linux

This article provides a quick guide to htop, an interactive system-monitor process-viewer designed for Unix-like systems. You will learn what htop is, how it improves upon the classic top utility, how to navigate its interface, and where to find its official documentation for advanced usage.

Understanding htop

htop is a free, open-source, and cross-platform interactive process manager. It provides a real-time, color-coded dynamic view of a system’s resource usage, including CPU, memory, and swap space. Unlike the traditional top command, htop offers a complete list of running processes instead of just the top resource-consuming ones. You can find detailed usage guides and installation instructions on the htop Command line tool documentation website.

Key Features of htop

Interactive Interface: Users can scroll vertically to view all processes and horizontally to see full command lines.
Ease of Use: You can perform actions like killing, prioritizing (renicing), or filtering processes without needing to type their Process IDs (PIDs).
Mouse Support: htop supports mouse clicks for navigating menus and selecting processes.
Visual Metrics: It uses clean, color-coded bars to represent CPU, memory, and swap usage at a glance.

How to Read the htop Display

The htop interface is divided into three main sections:

The Header (Top): Displays CPU usage per core, memory usage, swap usage, tasks count, load average, and system uptime.
The Main Body (Middle): Lists active processes. Columns show the PID, user, priority (PRI), niceness (NI), virtual memory (VIRT), resident memory (RES), CPU percentage, memory percentage, execution time, and the command name.
The Footer (Bottom): Shows a menu of function keys (F1 to F10) for quick actions such as searching (F3), filtering (F4), sorting (F6), killing processes (F9), and exiting (F10).

Using htop simplifies system administration by turning process management into a visual, straightforward task.