Arch Linux

Arch Linux () is a Linux distribution for computers with x86-64 processors. 
Arch Linux adheres to the KISS principle ("Keep It Simple, Stupid") and is focused on simplicity, modernity, pragmatism, user centrality, and versatility. In practice, this means the project attempts to have minimal distribution-specific changes, and therefore minimal breakage with updates, and be pragmatic over ideological design choices and focus on customizability rather than user-friendliness. 
A package manager written specifically for Arch Linux, Pacman, is used to install, remove and update software packages. Arch Linux uses a rolling release model, meaning there are no "major releases" of completely new versions of the system; a regular system update is all that is needed to obtain the latest Arch software; the installation images released every month by the Arch team are simply up-to-date snapshots of the main system components.
Arch Linux has comprehensive documentation, which consists of a community wiki known as the ArchWiki.
History.
Inspired by CRUX, another minimalist distribution, Judd Vinet started the Arch Linux project in March 2002. The name was chosen because Vinet liked the word's meaning of "the principal," as in "arch-enemy".
Originally only for 32-bit x86 CPUs, the first x86_64 installation ISO was released in April 2006.
Vinet led Arch Linux until 1 October 2007, when he stepped down due to lack of time, transferring control of the project to Aaron Griffin.
The migration to systemd as its init system started in August 2012, and it became the default on new installations in October 2012. It replaced the SysV-style init system, used since the distribution inception.
On 24 February 2020, Aaron Griffin announced that due to his limited involvement with the project, he would, after a voting period, transfer control of the project to Levente Polyak. This change also led to a new 2-year term period being added to the Project Leader position.
The end of i686 support was announced in January 2017, with the February 2017 ISO being the last one including i686 and making the architecture unsupported in November 2017. Since then, the community derivative Arch Linux 32 can be used for i686 hardware.
Repository security.
Until Pacman version 4.0.0, Arch Linux's package manager lacked support for signed packages. Packages and metadata were not verified for authenticity by Pacman during the download-install process. Without package authentication checking, tampered-with or malicious repository mirrors could compromise the integrity of a system. Pacman 4 allowed verification of the package database and packages, but it was disabled by default. In November 2011, package signing became mandatory for new package builds, and as of 21 March 2012, every official package is signed.
In June 2012, package signing verification became official and is now enabled by default in the installation process.
Design and principles.
Arch is largely based on binary packages. Packages target x86-64 microprocessors to assist performance on modern hardware. A ports/ebuild-like system is also provided for automated source compilation, known as the Arch Build System.
Arch Linux focuses on simplicity of design, meaning that the main focus involves creating an environment that is straightforward and relatively easy for the user to understand directly, rather than providing polished point-and-click style management tools — the package manager, for example, does not have an official graphical front-end. This is largely achieved by encouraging the use of succinctly commented, clean configuration files that are arranged for quick access and editing. This has earned it a reputation as a distribution for "advanced users" who are willing to use the command line.
Installation.
The Arch Linux website supplies ISO images that can be run from CD or USB. After a user partitions and formats their drive, a simple command line script (pacstrap) is used to install the base system. The installation of additional packages which are not part of the base system (for example, desktop environments), can be done with either pacstrap, or Pacman after booting (or chrooting) into the new installation.
An alternative to using CD or USB images for installation is to use the static version of the package manager Pacman, from within another Linux-based operating system. The user can mount their newly formatted drive partition, and use pacstrap (or Pacman with the appropriate command-line switch) to install base and additional packages with the mountpoint of the destination device as the root for its operations. This method is useful when installing Arch Linux onto USB flash drives, or onto a temporarily mounted device which belongs to another system.
Regardless of the selected installation type, further actions need to be taken before the new system is ready for use, most notably by installing a bootloader and configuring the new system with a system name, network connection, language settings, and graphical user interface.
The installation images come packaged with an experimental command line installer, archinstall, which can assist with installing Arch Linux.
Arch Linux does not schedule releases for specific dates but uses a "rolling release" system where new packages are provided throughout the day. Its package management allows users to easily keep systems updated.
Occasionally, manual interventions are required for certain updates, with instructions posted on the news section of the Arch Linux website.
Package management.
Arch Linux's only supported binary platform is x86_64. The Arch package repositories and User Repository (AUR) contain 58,000 binary and source packages, which comes close to Debian's 68,000 packages; however, the two distributions' approaches to packaging differ, making direct comparisons difficult. For example, six out of Arch's 58,000 packages comprise the software AbiWord, of which three in the user repository replace the canonical Abiword package with an alternative build type or version (such as sourcing from the latest commit to Abiword's source control repository), whereas Debian installs a single version of Abiword across seven packages. The Arch User Repository also contains a writerperfect package which installs several document format converters, while Debian provides each of the more than 20 converters in its own subpackage.
Pacman.
To facilitate regular package changes, Pacman (a contraction of "package manager") was developed by Judd Vinet to provide Arch with its own package manager to track dependencies. It is written in C.
All packages are managed using the Pacman package manager. Pacman handles package installation, upgrades, downgrades, removal, and features automatic dependency resolution. The packages for Arch Linux are obtained from the Arch Linux package tree and are compiled for the x86-64 architecture. It uses binary packages in the codice_1 (for zstd compression), with codice_2 placed before this to indicate that it is a Pacman package (giving codice_3).
As well as Arch Linux, Pacman is also used for installing packages under MSYS2 (a fork of Cygwin) on Windows.
Repositories.
The following official binary repositories exist:
Additionally, there are "testing" repositories which include binary package candidates for other repositories. Currently, the following testing repositories exist:
The "staging" and "community-staging" repositories are used for some rebuilds to avoid broken packages in "testing".
There are also two other repositories that include the newest version of certain desktop environments.
The "unstable" repository was dropped in July 2008 and most of the packages moved to other repositories. In addition to the official repositories, there are a number of unofficial user repositories.
The most well-known unofficial repository is the Arch User Repository, or AUR, hosted on the Arch Linux site. However, the AUR does not host binary packages, hosting instead a collection of build scripts known as PKGBUILDs.
The Arch Linux repositories contain both libre and nonfree software, and the default Arch Linux kernel contains nonfree proprietary blobs, hence the distribution is not endorsed by the GNU project.
Arch Build System (ABS).
The Arch Build System (ABS) is a ports-like source packaging system that compiles source tarballs into binary packages, which are installed via Pacman. The Arch Build System provides a directory tree of shell scripts, called "PKGBUILDs", that enable any and all official Arch packages to be customized and compiled. Rebuilding the entire system using modified compiler flags is also supported by the Arch Build System. The Arch Build System codice_4 tool can be used to create custom codice_5 packages from third-party sources. The resulting packages are also installable and trackable via Pacman.
Arch User Repository (AUR).
In addition to the repositories, the Arch User Repository (AUR) provides user-made PKGBUILD scripts for packages not included in the repositories. These PKGBUILD scripts simplify building from source by explicitly listing and checking for dependencies and configuring the install to match the Arch architecture. Arch User Repository helper programs can further streamline the downloading of PKGBUILD scripts and associated building process. However, this comes at the cost of executing PKGBUILDs not validated by a trusted person; as a result, Arch developers have stated that the utilities for automatic finding, downloading and executing of PKGBUILDs will never be included in the official repositories.
Users can create packages compatible with Pacman using the Arch Build System and custom PKGBUILD scripts. This functionality has helped support the Arch User Repository, which consists of user contributed packages to supplement the official repositories.
The Arch User Repository provides the community with packages that are not included in the repositories. Reasons include:
PKGBUILDs for any software can be contributed by ordinary users and any PKGBUILD that is not confined to the Arch User Repository for policy reasons can be voted into the community repositories.
Derivatives.
There are several projects working on porting the Arch Linux ideas and tools to other kernels, including PacBSD (formerly ArchBSD) and Arch Hurd, which are based on the FreeBSD and GNU Hurd kernels, respectively. There is also the Arch Linux ARM project, which aims to port Arch Linux to ARM-based devices, including the Raspberry Pi, as well as the Arch Linux 32 project, which continued support for systems with 32-bit only CPUs after the mainline Arch Linux project dropped support for the architecture in November 2017.
Logo.
The current Arch Linux logo was designed by Thayer Williams in 2007 as part of a contest to replace the previous logo.
Reception.
OSNews reviewed Arch Linux in 2002. OSNews also has 5 later reviews about Arch Linux.
LWN.net wrote a review about Arch Linux in 2005. LWN.net also has 2 later reviews about Arch Linux.
Tux Machines reviewed Arch Linux in 2007.
Chris Smart from DistroWatch Weekly wrote a review about Arch Linux in January 2009. DistroWatch Weekly reviewed Arch Linux again in September 2009, and in December 2015.
Linux maintainer Greg Kroah-Hartman has stated that he uses Arch and that it "works really really well," he also praised the Arch Wiki, and that the distribution stays close to upstream development, as well as the feedback loop with the community.