htop
interactive process viewer and system monitor
TLDR
Start htop
SYNOPSIS
htop [options]
DESCRIPTION
htop is an interactive, ncurses-based process viewer and system monitor designed as a more capable alternative to the traditional top command. Its full-screen interface displays per-core CPU utilization, memory, and swap usage as color-coded bar meters at the top, followed by a scrollable, sortable table of all running processes. Unlike top, htop supports full mouse interaction and intuitive keyboard shortcuts for everyday tasks.
Users can filter the process list in real time (F4), search for processes by name (F3), and toggle a tree view (F5) that reveals parent-child process hierarchies. Sending signals to processes is straightforward -- pressing F9 presents a menu of signals (SIGTERM, SIGKILL, SIGHUP, etc.) to send to one or more tagged processes. Process priority (nice value) can be adjusted directly, and the setup screen (F2) allows full customization of which columns and meters are displayed, persisted across sessions.
PARAMETERS
-u user, --user= user
Show only processes of specified user.-p pid, --pid= pid
Show only specified PIDs.-t, --tree
Start in tree view mode.-s column, --sort-key= column
Sort by specified column.-d delay, --delay= delay
Update interval in tenths of seconds.-C, --no-color
Monochrome mode.-F string, --filter= string
Show only processes containing string.-H, --highlight-changes
Highlight new/changed processes.--readonly
Disable process manipulation.
KEYBOARD CONTROLS
F1 / h: Help screen
F2 / S: Setup menu
F3 / /: Search
F4 / \\: Filter
F5 / t: Tree view toggle
F6 / >: Sort column menu
F9 / k: Kill process
F10 / q: Quit
Space: Tag process
U: Untag all
c: Tag and children
CAVEATS
Some features require root privileges (changing priorities, killing other users' processes). High refresh rates may impact system performance. Process information is a snapshot and may change between refreshes.
HISTORY
htop was created by Hisham Muhammad in 2004 as a more user-friendly process viewer for Linux. It addressed common complaints about top's interface and lack of interactivity. The project was later forked as htop-dev by a community group after maintenance lapsed. htop has become the de facto interactive process viewer on Linux systems.