Usage
There is no single "apt" program; apt is itself the package name containing the set of tools (and requiring the libraries) that support its functionality. A significant part of apt is a C++ library of functions (another package known as libapt) which are used by these related front-end programs for dealing with packages, such as apt-get and apt-cache. They are commonly used in examples due to their simplicity and ubiquity; apt-get and apt-cache are of "important" priority in all current Debian releases, and are therefore installed in a default Debian installation. Apt can be functionally considered to be a front-end to dpkg, and a friendlier front end to this than dselect. While dpkg performs actions on individual packages, apt tools manage relations (especially dependencies) between them, as well as sourcing and management of higher-level versioning decisions (release tracking and version pinning).
APT is often hailed as one of Debian's best features. It is remarked that this quality comes from the strict quality controls of Debian policy.
A major feature in 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. In some cases, it utilizes the --force options in dpkg. However, it only does this when it is unable to calculate how to avoid the reason dpkg requires the action to be forced.
Read more about this topic: Advanced Packaging Tool
Famous quotes containing the word usage:
“...Often the accurate answer to a usage question begins, “It depends.” And what it depends on most often is where you are, who you are, who your listeners or readers are, and what your purpose in speaking or writing is.”
—Kenneth G. Wilson (b. 1923)
“Girls who put out are tramps. Girls who don’t are ladies. This is, however, a rather archaic usage of the word. Should one of you boys happen upon a girl who doesn’t put out, do not jump to the conclusion that you have found a lady. What you have probably found is a lesbian.”
—Fran Lebowitz (b. 1951)
“I am using it [the word ‘perceive’] here in such a way that to say of an object that it is perceived does not entail saying that it exists in any sense at all. And this is a perfectly correct and familiar usage of the word.”
—A.J. (Alfred Jules)