htop/README.md

Introduction

htop is a cross-platform interactive process viewer.

htop allows scrolling the list of processes vertically and horizontally to see their full command lines and related information like memory and CPU consumption. Also system wide information, like load average or swap usage, is shown.

The information displayed is configurable through a graphical setup and can be sorted and filtered interactively.

Tasks related to processes (e.g. killing and renicing) can be done without entering their PIDs.

Running htop requires ncurses libraries, typically named libncurses(w).

htop is written in C.

For more information and details visit htop.dev.

Build instructions

Prerequisite

List of build-time dependencies:

• standard GNU autotools-based C toolchain
  • C99 compliant compiler
  • autoconf
  • automake
  • autotools
• ncurses

Note about ncurses:

htop requires ncurses 6.0. Be aware the appropriate package is sometimes still called libncurses5 (on Debian/Ubuntu). Also ncurses usually comes in two flavours:

• With Unicode support.
• Without Unicode support.

This is also something that is reflected in the package name on Debian/Ubuntu (via the additional 'w' - 'w'ide character support).

List of additional build-time dependencies (based on feature flags):

• pkg-config
• sensors
• hwloc
• libcap (v2.21 or later)
• libnl-3 and libnl-genl-3

pkg-config is optional but recommended. The configure script of htop might utilize pkg-config to obtain the compiler and linker flags required for a library. Some OS distributions provide pkg-config functionalities through an alternative implementation such as pkgconf. Look for both names in your package manager.

Install these and other required packages for C development from your package manager.

Debian/Ubuntu

sudo apt install libncursesw5-dev autotools-dev autoconf automake build-essential

Fedora/RHEL

sudo dnf install ncurses-devel automake autoconf gcc

Archlinux/Manjaro

sudo pacman -S ncurses automake autoconf gcc

macOS

brew install ncurses automake autoconf gcc

Compile from source:

To compile from source, download from the Git repository (git clone or downloads from GitHub releases), then run:

./autogen.sh && ./configure && make

Install

To install on the local system run make install. By default make install installs into /usr/local. To change this path use ./configure --prefix=/some/path.

Build Options

htop has several build-time options to enable/disable additional features.

Generic

• --enable-unicode: enable Unicode support
  • dependency: libncursesw
  • default: yes
• --enable-affinity: enable sched_setaffinity(2) and sched_getaffinity(2) for affinity support; conflicts with hwloc
  • default: check
• --enable-hwloc: enable hwloc support for CPU affinity; disables affinity support
  • dependency: libhwloc
  • default: no
• --enable-static: build a static htop binary; hwloc and delay accounting are not supported
  • default: no
• --enable-debug: Enable asserts and internal sanity checks; implies a performance penalty
  • default: no

Performance Co-Pilot

• --enable-pcp: enable Performance Co-Pilot support via a new pcp-htop utility
  • dependency: libpcp
  • default: no

Linux

• --enable-sensors: enable libsensors(3) support for reading temperature data
  • dependencies: libsensors-dev(build-time), at runtime libsensors is loaded via dlopen(3) if available
  • default: check
• --enable-capabilities: enable Linux capabilities support
  • dependency: libcap
  • default: check
• --with-proc: location of a Linux-compatible proc filesystem
  • default: /proc
• --enable-openvz: enable OpenVZ support
  • default: no
• --enable-vserver: enable VServer support
  • default: no
• --enable-ancient-vserver: enable ancient VServer support (implies --enable-vserver)
  • default: no
• --enable-delayacct: enable Linux delay accounting support
  • dependencies: libnl-3-dev(build-time) and libnl-genl-3-dev(build-time), at runtime libnl-3 and libnl-genl-3 are loaded via dlopen(3) if available and requested
  • default: check

Runtime dependencies:

htop has a set of fixed minimum runtime dependencies, which is kept as minimal as possible:

• ncurses libraries for terminal handling (wide character support).

Runtime optional dependencies:

htop has a set of fixed optional dependencies, depending on build/configure option used:

Linux

• libdl, if not building a static binary, is always required when support for optional dependencies (i.e. libsensors, libsystemd) is present.
• libcap, user-space interfaces to POSIX 1003.1e capabilities, is always required when --enable-capabilities was used to configure htop.
• libsensors, readout of temperatures and CPU speeds, is optional even when --enable-sensors was used to configure htop.
• libsystemd is optional when --enable-static was not used to configure htop. If building statically and libsystemd is not found by configure, support for the systemd meter is disabled entirely.
• libnl-3 and libnl-genl-3, if htop was configured with --enable-delayacct and delay accounting process fields are active.
• I/O counters are available when the kernel is compiled with CONFIG_TASK_IO_ACCOUNTING=Y.

htop checks for the availability of the actual runtime libraries as htop runs.

BSD

On most BSD systems kvm is a requirement to read kernel information.

More information on required and optional dependencies can be found in configure.ac.

Usage

See the manual page (man htop) or the help menu (F1 or h inside htop) for a list of supported key commands.

Support

If you have trouble running htop please consult your operating system / Linux distribution documentation for getting support and filing bugs.

Bugs, development feedback

We have a development mailing list. Feel free to subscribe for release announcements or asking questions on the development of htop.

You can also join our IRC channel #htop on Libera.Chat and talk to the developers there.

If you have found an issue within the source of htop, please check whether this has already been reported in our GitHub issue tracker. If not, please file a new issue describing the problem you have found, the potential location in the source code you are referring to and a possible fix if available.

History

htop was invented, developed and maintained by Hisham Muhammad from 2004 to 2019. His legacy repository has been archived to preserve the history.

In 2020 a team took over the development amicably and continues to maintain htop collaboratively.

License

GNU General Public License, version 2 (GPL-2.0) or, at your option, any later version.