#DEBIAN PACKAGE MANAGER HOW TO#
#DEBIAN PACKAGE MANAGER INSTALL#
#DEBIAN PACKAGE MANAGER UPDATE#
#DEBIAN PACKAGE MANAGER SOFTWARE#

#DEBIAN PACKAGE MANAGER INSTALL#

upgrade is used to install the newest versions of all packages currently installed on the system from the sources enumerated in /etc/apt/sources.list.

For example, when using a Debian archive, this command retrieves and scans the Packages.gz files, so that information about new and updated packages is available. The lists of available packages are fetched from the location(s) specified in /etc/apt/sources.list.

#DEBIAN PACKAGE MANAGER UPDATE#

update is used to resynchronize the package index files from their sources.

Usage modes of apt and apt-get that facilitate updating installed packages include: Triggers are the treatment of deferred actions. The user can specify packages using a POSIX regular expression.ĪPT searches its cached list of packages and lists the dependencies that must be installed or updated.ĪPT retrieves, configures and installs the dependencies automatically.

#DEBIAN PACKAGE MANAGER SOFTWARE#

This can downgrade a package and render dependent software inoperable, so the user must be careful.įinally, the apt_preferences mechanism allows the user to create an alternative installation policy for individual packages. One option is to force a particular version of a package. APT uses a location configuration file ( /etc/apt/sources.list) to locate the desired packages, which might be available on the network or a removable storage medium, for example, and retrieve them, and also obtain information about available (but not installed) packages.ĪPT provides other command options to override decisions made by apt-get's conflict resolution system. This was an original distinguishing characteristic of APT-based package management systems, as it avoided installation failure due to missing dependencies, a type of dependency hell.Īnother distinction is the retrieval of packages from remote repositories. Notably, APT automatically gets and installs packages upon which the indicated package depends (if necessary). Each package name is phrased as just the name portion of the package, not a fully qualified filename (for instance, in a Debian system, libc6 would be the argument provided, not libc6_1.9.6-2.deb). The user indicates one or more packages to be installed.

#DEBIAN PACKAGE MANAGER HOW TO#

However, it only does this when it is unable to calculate how to avoid the reason dpkg requires the action to be forced.

In some cases, it utilizes the -force options of dpkg. Ī major feature of APT is the way it calls dpkg - it does topological sorting of the list of packages to be installed or removed and calls dpkg in the best possible sequence. While dpkg performs actions on individual packages, APT manages relations (especially dependencies) between them, as well as sourcing and management of higher-level versioning decisions (release tracking and version pinning).ĪPT is often hailed as one of Debian's best features, which Debian developers attribute to the strict quality controls in Debian's policy.

APT can be considered a front-end to dpkg, friendlier than the older dselect front-end. The apt package is of ' important' priority in all current Debian releases, and is therefore included in a default Debian installation. They are commonly used in examples because they are simple and ubiquitous. Three such programs are apt, apt-get and apt-cache. A significant part of APT is defined in a C++ library of functions APT also includes command-line programs for dealing with packages, which use the library.

Usage ĪPT is a collection of tools distributed in a package named apt. APT simplifies the process of managing software on Unix-like computer systems by automating the retrieval, configuration and installation of software packages, either from precompiled files or by compiling source code. Advanced package tool, or APT, is a free-software user interface that works with core libraries to handle the installation and removal of software on Debian, and Debian-based Linux distributions.

Debian package manager