This post was originally published on go2linux.org on August 6, 2007. The domain is no longer mine, but I am the original author. I am republishing it here on garron.me with corrections and improvements.
Almost every Linux user has used top to check how the system is doing — running processes, CPU usage, memory. But top has limitations: it truncates long process names, the interface is not very intuitive, and killing a process requires you to know its PID and type it manually.
That is where htop comes in.
Installing htop
# Debian / Ubuntu
sudo apt install htop
# Fedora / RHEL / CentOS
sudo dnf install htop
# Arch Linux
sudo pacman -S htop
Basic usage
Just type:
htop
At the top you will see a bar for each CPU core, plus memory and swap usage. Below that is the process list, sorted by CPU usage by default.
Keyboard shortcuts
This is where htop really shines over top. You do not need to memorize cryptic key combinations — the function keys are shown at the bottom of the screen.
| Key | Action |
|---|---|
F2 |
Setup — customize colors, columns, and display options |
F3 |
Search — find a process by name as you type |
F4 |
Filter — show only processes matching a string |
F5 |
Tree view — show processes in a parent/child hierarchy |
F6 |
Sort — choose which column to sort by |
F9 |
Kill — send a signal to the selected process |
F10 |
Quit |
Space |
Tag a process (to kill or act on multiple at once) |
u |
Filter by user |
t |
Toggle tree view |
Mouse support
htop supports the mouse. You can click on a column header to sort by it, click on a process to select it, and click the function key labels at the bottom to activate them. Not all terminals support this, but most modern ones do.
Useful flags
Show processes as a tree from the start:
htop --tree
Sort by memory usage:
htop --sort-key PERCENT_MEM
I use htop daily on every server I manage. Once you get used to it, going back to plain top feels like a step backwards. The first tool I install on every Linux system is htop.