# htop — Interactive Process Viewer for Unix Systems

> A cross-platform interactive process viewer that provides a color-coded, scrollable overview of system resources and running processes in the terminal.

## Install

Save as a script file and run:

# htop — Interactive Process Viewer for Unix Systems

## Quick Use
```bash
# Install
sudo apt install htop   # Debian/Ubuntu
brew install htop       # macOS
# Run
htop
# Filter by process name
htop -F nginx
```

## Introduction
htop is an interactive process viewer and system monitor for Unix-like systems. It improves on the classic top command with a colorful interface, mouse support, vertical and horizontal scrolling, and the ability to manage processes without typing PIDs.

## What htop Does
- Displays real-time CPU, memory, and swap usage with color-coded meters
- Lists all running processes with sortable columns for CPU, memory, I/O, and more
- Allows interactive process management: kill, renice, and send signals with a keystroke
- Filters and searches processes by name, user, or command line
- Supports tree view to visualize parent-child process relationships

## Architecture Overview
htop reads process information from /proc on Linux and equivalent interfaces on macOS and FreeBSD. It uses ncurses for terminal rendering. The display loop polls system stats at a configurable interval and redraws meters and the process table. Columns, meters, and layouts are customizable through the setup screen (F2) and persisted to ~/.config/htop/htoprc.

## Self-Hosting & Configuration
- Install from your distribution package manager or Homebrew on macOS
- Press F2 to open the setup screen and configure visible columns and meters
- Customize header layout with CPU meters, memory bars, uptime, and load average
- Set update interval and color scheme in the interactive configuration
- Configuration is saved to ~/.config/htop/htoprc in a human-readable format

## Key Features
- Full mouse support for clicking columns, scrolling, and selecting processes
- Tree view shows process hierarchy at a glance
- Per-core CPU meters and I/O wait visualization
- Filter processes interactively by name, user, or cgroup
- Cross-platform: runs on Linux, macOS, FreeBSD, OpenBSD, and Solaris

## Comparison with Similar Tools
- **top** — pre-installed on all Unix systems; less interactive, no mouse support
- **btop** — newer alternative with richer visualizations; written in C++
- **glances** — Python-based with web UI and export plugins; heavier dependencies
- **atop** — records system activity for historical analysis; steeper learning curve

## FAQ
**Q: How is htop different from top?**
A: htop provides color-coded output, mouse interaction, horizontal scrolling for long command lines, tree view, and interactive filtering that top lacks.

**Q: Can htop show per-container or per-cgroup usage?**
A: htop supports cgroup-based filtering and can display cgroup columns to distinguish container workloads.

**Q: Does htop work over SSH?**
A: Yes. It runs in any terminal emulator over SSH, making it useful for remote server monitoring.

**Q: How do I kill a process in htop?**
A: Select the process with arrow keys or mouse, press F9, choose a signal (default SIGTERM), and confirm.

## Sources
- https://github.com/htop-dev/htop
- https://htop.dev/

---
Source: https://tokrepo.com/en/workflows/asset-6334d257
Author: Script Depot