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This article uses easy-to-understand examples to introduce what apt means in linux. The code is very detailed. Interested friends can use it for reference. I hope it will be helpful to you.

Introduction to apt

Advanced Packaging Tool (apt) is an installation package management tool under Linux.

Initially, there was only a .tar.gz package file, and the user had to compile every software he wanted to run on GNU/Linux. Users generally think that it is necessary for the system to provide a way to manage these software packages installed on the machine. When Debian was born, such a management tool came into being, which was named dpkg.

Thus the famous concept of "package" appeared in the GNU/Linux system for the first time, and later Red Hat decided to develop its own "rpm" package management system.

Soon a new problem baffled GNU/Linux makers who needed a fast, practical, and efficient way to install packages that should automatically manage associated files and maintain existing configuration files when the package is updated.

Debian once again took the lead in solving this problem, and APT (Advanced Packaging Tool) was born as the front end of dpkg. APT was later transformed by Conectiva to manage rpm and adopted as their package management tool by other Linux distributions.

APT consists of several programs whose names start with "apt-". Apt-get, apt-cache, and apt-cdrom are command-line tools for processing software packages.

The Linux command-apt, is also the back end of other user foreground programs, such as dselect and aptitude.

As part of the operation, APT uses a file that lists the image site address of the available package, which is / etc/apt/sources.list.

working principle

APT is a client / server system. Copy all DEB packages on the server first (DEB is the file extension of the Debian package format), then use APT's analysis tool (genbasedir) to analyze all DEB packages according to the Header information of each DEB package, and record the analysis results in a file called DEB index list, and the APT server DEB index list is placed in the base folder.

Once the DEB in the APT server changes, be sure to use genbasedir to generate a new DEB index list. When the client installs or upgrades, it first queries the DEB index list so that it can learn about all dependent software packages and download them to the client for installation.

When the client needs to install, upgrade or delete a software package, the client computer gets the DEB index list zip file and unzips it to / var/state/apt/lists/,. When the client uses the apt-get install or apt-get upgrade command, it compares the data in this folder with the DEB database on the client computer to know which DEB has been installed, not installed, or can be upgraded.

About what the meaning of apt in linux is shared here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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