Linux Command: htop

htop is an interactive process viewer with an improved, color-coded interface compared to top. It provides real-time monitoring of CPU, memory, and swap usage with visual bar graphs and supports mouse interaction. htop shows individual CPU cores, memory and swap bars, load average, uptime, and a scrollable process list with tree view support. It allows direct process management — killing, renicing, and sending signals — without needing to type PIDs. htop is widely considered the superior alternative to top for daily system monitoring. It is more user-friendly, supports horizontal scrolling for long command lines, and provides better process tree visualization.

Syntax

htop [OPTION]...

Key Options

• -d — Set update delay in tenths of seconds
• -u — Show only processes of a user
• -p — Monitor specific PIDs
• -t — Start in tree view mode
• -s — Sort by column
• -C — Monochrome mode (no colors)

Examples

Standard monitoring

htop

Tree view

htop -t

Monitor specific user

htop -u nginx

Pro Tips

• F2=Setup, F3=Search, F4=Filter, F5=Tree, F6=Sort, F9=Kill, F10=Quit. Also: / to search, \ to filter, Space to tag.
• Blue=low priority, Green=normal, Red=kernel, Cyan=virtualization. Understanding colors helps identify what is consuming CPU.
• htop is not installed by default on many systems. Install with: apt install htop (Debian/Ubuntu) or yum install htop (RHEL).

Learn more: Full htop reference →