Advanced Packaging Tool, which has since been ported by Conectiva for use with rpm and has been adopted by several other distributions. The command apt-get is a powerful command line tools that are used to working with Ubuntu's Advanced Packaging Tool (APT) performing such functions as installation package of new software, upgrade software packages available, updating the list packet index, and even improve the entire Ubuntu system.
APT uses a file that lists the 'sources' from which packages can be obtained. This file is / etc / apt / sources.list.
The entries in this file follows this format
deb http://host/ubuntu distribution section1 section2 section3
deb-src http://host/ubuntu distribution section1 section2 section3
The first word on each line, deb or deb-src, indicates the type of archive: whether it contains binary packages (deb), that is pre-compiled packages that we normally use, or source packages (deb-src), now we will see commands available for apt-get
Update list of available packages
Packaging systems use private databases to track the package installed, which is not attached and are available for installation. The program apt-get uses this database to find out how to install packages requested by the user and to determine the additional packages needed for the selected package to work properly.
sudo apt-get update
The following options to apt-get may be useful
-H This help text.
-D Download only - DO NOT install or unpack archives
-F Attempt to continue if the integrity check fails
-S No-act. Perform ordering simulation
-Y Assume Yes to all questions and do not encourage
-U Show a list of upgraded packages as well
Installing Packages Using apt-get
sudo apt-get install packagename
Example
sudo apt-get install apache2
Using apt-get package re-
If you somehow damage an installed package, or just want a file from a package that will be reinstalled with the latest version available, you can use the - reinstall option
sudo apt-get - reinstall install packagename
sudo apt-get - reinstall install apache2
Delete Using apt-get package
sudo apt-get remove packagename
Example
sudo apt-get remove apache2
Running apt-get as above will cause packets to be deleted, but their configuration files, if any, will remain intact on the system. For a complete removal of the package
sudo apt-get - purge remove packagename
Example
sudo apt-get - purge remove apache2
As in the case of installation methods, you can use a symbol with remove to invert the meaning for a particular package. In the case of moving, if you add a '+' right after the name of the package, the package will be installed instead of removed.
sudo apt-get - purge remove packagename +
Example
sudo apt-get - purge remove apache2 +
Upgrade Package
You can use this command to upgrade packages in the same distribution, as well as to upgrade to a new distribution
sudo apt-get-u upgrade
Upgrades to new releases
sudo apt-get-u dist-upgrade
If you want to upgrade a specific package using the following command
sudo apt-get-u install packagename
Example
sudo apt-get-u install apache2
Remove unused package files
When you install a package APT takes the necessary files from the hosts listed in / etc / apt / sources.list, stores them in a local repository (/ var / cache / apt / archives /), and then proceed with the installation. Within the local repository can grow and occupy a lot of disk space. Fortunately, APT provides tools for managing a local repository.
apt-get clean removes everything except lock files from / var / cache / apt / archives / and / var / cache / apt / archives / partial /. So, if you need to reinstall a package APT should retrieve again.
sudo apt-get clean
apt-get autoclean only removes package files that are no longer available for download.
sudo apt-get autoclean
Find a specific packge
If you want to find a specific packge using the apt-cache. This program is used by the APT system to maintain its database.
Search for specific package
sudo apt-cache search packagename
Example
sudo apt-cache search atari
If you want to get more information about a specific package using the following command
sudo apt-cache show packagename
Example
sudo apt-cache show nagios3
If you want to know what packages it depends on the particular package
sudo apt-cache depends packagename
Example
sudo apt-cache depends nagios3
How to find which package the file belongs
If you want to install a package, and you can not find what is called by searching with apt-cache, but knowing the file name of the program itself, or another file name that is owned by the package, then you can use apt-file to find the package name . This is done like this:
sudo apt-file search filename
You also can list the contents of a package, by running
sudo apt-file list packagename
apt-file that stores the database file that contains all the packages, such as auto-apt does and needs to be up-to-date. This is done by running:
sudo apt-file update
Downloading source packages
To download the source package, you will use the following command:
sudo apt-get source packagename
This will download three files: a. Orig.tar.gz, a. Dsc and. Diff.gz. In the case of packages made specifically for Ubuntu, the latter is not downloaded and the first usually will not have the "original" in the name.
The. Dsc file used by dpkg-source to unpack the source package into the directory packagename-version. In each downloaded source package there is debian / directory that contains the files needed to create. Deb package.
To automatically build the package when it is downloaded, just add-b to the command line
sudo apt-get-b source packagename
Packages required to compile a source package
Typically, specific headers and shared libraries need to be present so that the source package to be compiled. All source packages have a column in their control file called 'Build-Depends:' that indicates additional packages needed for the package to be built from source. APT has a simple way to download these packages.
sudo apt-get build-dep package
Example
sudo apt-get build-dep GMC
