Linux htop Command: Explore Processes Interactively

htop is a tool for exploring CPU and memory usage and the list of processes on an interactive screen. You can easily search, filter, and sort, but depending on the distribution, a separate installation may be required.

What is the htop command?

You can select a process row and examine the target using keyboard functions. Generally, F3 is search, F4 is filter, and F10 is exit. Key mappings may vary depending on the version and terminal settings, so check the on-screen help as well.

Basic syntax

htop [options]

Installed implementations and options may differ depending on the distribution. Use man htop to see the description on the current system.

Examples

Open the interactive screen

Check the top resource usage and the process list below together.

htop

View only specific user tasks

Narrow the scope to the processes of the user being managed.

htop -u alice

Focus on a specific PID

Observe the status of processes that have already been checked.

htop -p 1234

Interactive Screen Reading

htop is an interactive tool that displays CPU usage per core and memory/swap usage at the top, and a list of processes at the bottom. Unlike typical commands that produce a fixed number of lines of output, the screen continuously updates.

htop

Example of display structure (actual numbers and column layout vary depending on settings):

CPU  [####....]  Mem [##......]
PID   USER    CPU%  MEM%  COMMAND
...   ...     ...   ...   ...

You can search by name with F3, change the sorting criteria with F6, and exit with F10 or q. Key bindings may vary depending on the installed version and terminal. When terminating a process, first check the PID and the full command line, and use only the required permissions.

Main Options and Format

Precautions when using

htop may not be installed by default. Before installing the package, check the repository and package name of your distribution. The feature to send signals from the screen actually affects processes, so double-check the search results and PID, and processes without execution permissions may not be controllable.

Frequently Asked Questions

What should I do if htop is not available?

You can first check with top or ps. If you need htop, verify whether it is provided in the official package repository of your distribution.

Official Documentation

The exact behavior of options and differences by implementation can be checked in the official htop documentation.