Past
pacman and pkgfilepacman the package management system
In the October meeting, we discussed some of the most popular usages of
Introduction pacman is a utility which manages software packages in Linux. It uses simple compressed files as a package format, and maintains a text-based package database (more of a hierarchy), just in case some hand tweaking is necessary. pacman does not strive to "do everything." It will add, remove and upgrade packages in the system, and it will allow you to query the package database for installed packages, files and owners. It also attempts to handle dependencies automatically and can download packages from a remote server. History: Version 2.0 of pacman introduced the ability to sync packages (the --sync option) with a master server through the use of package databases. Prior to this, packages would have to be installed manually using the --add and --upgrade operations. Version 3.0 was the switch to a two-part pacman?—?a back-end named libalpm (library for Arch Linux Package Management) and the familiar pacman front-end. Speed in many cases was improved, along with dependency and conflict resolution being able to handle a much wider variety of cases. The switch to a library-based program should also make it easier in the future to develop alternative front ends. Version 4.0 added package signing and verification capabilities to the entire makepkg/repo-add/pacman toolchain via GnuPG and GPGME. Version 5.0 added support for pre/post-transaction hooks and sync database file list operations. [From the manfile]: pacman DESCRIPTION Pacman is a package management utility that tracks installed packages on a Linux system. It features dependency support, package groups, install and uninstall scripts, and the ability to sync your local machine with a remote repository to automatically upgrade packages. Pacman packages are a zipped tar format.
Since version 3.0.0, pacman has been the front-end to libalpm(3), the “Arch Linux Package Management” library. This library allows alternative front-ends to be written (for instance, a GUI front-end).
Invoking pacman involves specifying an operation with any potential options and targets to operate on. A target is usually a package name, file name, URL, or a search string. Targets can be provided as command line arguments. Additionally, if stdin is not from a terminal and a single hyphen (-) is passed as an argument, targets will be read from stdin.
The popular commands we discussed in the meeting: for pacman pacman -Syu #to update the entire system, (all packages) Explainations: -S, --sync Synchronize packages. Packages are installed directly from the remote repositories, including all dependencies required to run the packages. For example, pacman -S qt will download and install qt and all the packages it depends on. If a package name exists in more than one repository, the repository can be explicitly specified to clarify the package to install: pacman -S testing/qt. You can also specify version requirements: pacman -S "bash>=3.2". Quotes are needed, otherwise the shell interprets ">" as redirection to a file.
In addition to packages, groups can be specified as well. For example, if gnome is a defined package group, then pacman -S gnome will provide a prompt allowing you to select which packages to install from a numbered list. The package selection is specified using a space- and/or comma-separated list of package numbers. Sequential packages may be selected by specifying the first and last package numbers separated by a hyphen (-). Excluding packages is achieved by prefixing a number or range of numbers with a caret (^).
Packages that provide other packages are also handled. For example, pacman -S foo will first look for a foo package. If foo is not found, packages that provide the same functionality as foo will be searched for. If any package is found, it will be installed. A selection prompt is provided if multiple packages providing foo are found.
You can also use pacman -Su to upgrade all packages that are out-of-date. See Sync Options below. When upgrading, pacman performs version comparison to determine which packages need upgrading. This behavior operates as follows:
Alphanumeric: 1.0a < 1.0b < 1.0beta < 1.0p < 1.0pre < 1.0rc < 1.0 < 1.0.a < 1.0.1 Numeric: 1 < 1.0 < 1.1 < 1.1.1 < 1.2 < 2.0 < 3.0.0
Additionally, version strings can have an epoch value defined that will overrule any version comparison, unless the epoch values are equal. This is specified in an epoch:version-rel format. For example, 2:1.0-1 is always greater than 1:3.6-1.
-y, --refresh Download a fresh copy of the master package database from the server(s) defined in pacman.conf(5). This should typically be used each time you use --sysupgrade or -u. Passing two --refresh or -y flags will force a refresh of all package databases, even if they appear to be up-to-date.
-u, --sysupgrade Upgrades all packages that are out-of-date. Each currently-installed package will be examined and upgraded if a newer package exists. A report of all packages to upgrade will be presented, and the operation will not proceed without user confirmation. Dependencies are automatically resolved at this level and will be installed/upgraded if necessary.
Pass this option twice to enable package downgrades; in this case, pacman will select sync packages whose versions do not match with the local versions. This can be useful when the user switches from a testing repository to a stable one.
Additional targets can also be specified manually, so that -Su foo will do a system upgrade and install/upgrade the "foo" package in the same operation. pacman -S # To install packages (listed packages or suites of packages) (package names separated by spaces) … but you can also use -Syu to install package(s) and upgrade everything as well.
pacman -U # To install from file. (You can cd to directory with downloaded and use this command to install the package)
-U, --upgrade Upgrade or add package(s) to the system and install the required dependencies from sync repositories. Either a URL or file path can be specified. This is a “remove-then-add” process. See Upgrade Options below; also see Handling Config Files for an explanation on how pacman takes care of configuration files.
pacman -Ss # To search for a package
-s, --search <regexp> Search each locally-installed package for names or descriptions that match regexp. When including multiple search terms, only packages with descriptions matching ALL of those terms are returned.
pkfile DESCRIPTION pkgfile searches the .files metadata created by repo-add(8) to retrieve file information about packages. By default, the provided target is considered to be a filename and pkgfile will return the package(s) which contain this file. The repos which pkgfile searches is determined by those enabled in /etc/pacman.conf.
The popular usages of pkgfile: pkgfile <file-name-here> # Search for a command or package that may be part of a package a suite of packages, (such as ifconfig) Examples: $ pkgfile ifconfig core/net-tools $ pkgfile iwconfig core/wireless_tools $ pkgfile convert extra/imagemagick Of course, if the command is the same name of one single package, here is what you get: $ pkgfile nmap extra/nmap Although the package manager itself is quite simple, many scripts have been developed that help automate building and installing packages. These are used extensively in Arch Linux. Most of these utilities are available in the Arch Linux projects code browser. Other Utilities Utilities available:
srcpac - a bash build-from-source pacman wrapper
========================================= Here is a list of Linux Distributions that use pacman as their package
Mailing Lists |
||
|