APT Packaging Management Tool In Detail; Linux
A package is a ‘Software’. Examples of the package can be the browsers (Google chrome, Mozilla, Safari etc.), utilities package (ccleaner, ASC, BleachBit etc.), designing program (Photoshop, Gimp etc.) and Games (Need for Speed, Call of Duty etc.). The packages/software are compiled and set altogether so that when someone executes them, all the files or scripts start and install the programs on the system. Sometimes the compiled code is provided in which everything is setup, all the files and scripts, only thing user do is execute them. Mostly programs are packaged so that user can easily install it.
That packaged code need to be unpackaged or execute through ‘Package Management Tools’. That’s where newbies have problem/confusion in Linux.
While turning from Windows/Mac to Linux, one of the biggest problems is to understand the packaging management tools in Linux. The first confusion understanding software installation is different types of packaging tools for different Linux distributions and second is in Windows we’ve simply a setup.exe file clicking on which starts the installation. In Linux also we’ve such files to install programs but they get changed in other Linux Distributions. In this Article I am only heading to APT. To see other packaging Management tools, just see my article How To Install Software In Linux : An Introduction
Introduction to APT
As I mentioned above for different distributions we’ve different packaging management tools and so APT is for the Linux Debian based distributions. APT stands for Advanced Package Tool. In the beginning the .tar.gz (source code) was given that users had to compile them before they install on their GNU/Linux system. When the debian was created then they thought to make change and they designed a packaging management/system called dpkg. Then Red Hat after a while created rpm system. Then there was another challenge to install those packages easily and efficiently on systems with configuring perfectly and manage dependencies automatically. Then Debian created APT, Advanced Packaging Tool, since then has been being used in several other Linux distributions.
It was all needed to know for understanding the basics of the packaging and packaging management tools. Keep in mind the packaging management tools are the tools to execute programs in different ways. Here I’m going to tell you that how you can install/Unpack/configure any software (i.e package) through a widely used tool APT. It’s all done in terminal, don’t get scared it is super easy! And yeh! It can also remove/uninstall, update and upgrade any packages from the system as well. So It’s very featured.
How to use APT to install software : Commands
Each command needs user to be in root or using sudo. Read here more about sudo.
APT Installations commands
apt-get install {package_name}
It will install a new package
apt-get build-dep {package_name}
This command searches the repositories and installs the build dependencies for . If the package is not in the repositories it will return an error.
aptitude install {package_name}
Aptitude is an Ncurses viewer of packages installed or available. Aptitude can be used from the command line in a similar way to apt-get. See man aptitude for more information.
APT and aptitude will accept multiple package names as a space delimited list. For example:
apt-get install {package1_name} {package2_name} {package3_name}
Use the -s flag to simulate an action.”sudo apt-get -s install ” will simulate installing the package showing you what packages will be installed and configured
How to maintain linux: Commands
apt-get update
Run this command periodically to make sure your source list is up-to-date. This is the equivalent of “Reload” in Synaptic or “Fetch updates” in Adept.
apt-get upgrade
This command upgrades all installed packages. This is the equivalent of “Mark all upgrades” in Synaptic.
apt-get dist-upgrade
It tells APT to use “smart” conflict resolution system, and it will attempt to upgrade the most important packages at the expense of less important ones if necessary.
apt-get check
This command is a diagnostic tool. It does an update of the package lists and checks for broken dependencies.
apt-get -f install
This command does the same thing as Edit->Fix Broken Packages in Synaptic. Do this if you get complaints about packages with “unmet dependencies”.
apt-get autoclean
The command removes .deb files for packages that are no longer installed on your system. Depending on your installation habits, removing these files from /var/cache/apt/archives may regain a significant amount of diskspace.
apt-get clean
The same as above, except it removes all packages from the package cache. This may not be desirable if you have a slow Internet connection, since it will cause you to redownload any packages you need to install a program.
The package cache is in /var/cache/apt/archives . The command
du -sh /var/cache/apt/archives
will tell you how much space cached packages are consuming.
dpkg-reconfigure {package_name}
Reconfigure the named package. With many packages, you’ll be prompted with some configuration questions you may not have known were there.
echo ” hold” | dpkg –set-selections
 This command may have the unintended side effect of preventing upgrades to packages that depend on updated versions of the pinned package. apt-get dist-upgrade will override this, but will warn you first. If you want to use this command with sudo, you need to use echo ” hold” | sudo dpkg –set-selections not sudo echo ” hold” | dpkg –set-selections.
echo ” install” | dpkg –set-selections
This command removes the “hold” or “locked package” state set by the above command. The note above about sudo usage applies to this command.
How to remove packages: Commands
apt-get remove {package_name}
This command removes an installed package, leaving configuration files intact.
apt-get purge {package_name}
This command completely removes a package and the associated configuration files. Configuration files residing in ~ are not usually affected by this command.
+ operator
apt-get remove {package1} {package2}+
apt-get remove {package1} {package2}+
This command removes packages that were installed by other packages and are no longer needed.
apt-get autoremove {package_name}
This command removes an installed package and dependencies.
While there is no built in way to remove all of your configuration information from your removed packages you can remove all configuration data from every removed package with the following command.
dpkg -l | grep ‘^rc’ | awk ‘{print $2}’ | xargs dpkg –purge
How to search package in Linux: Commands
apt-cache search {search_term)
This command will find packages that include {search_term}.
dpkg -l *{search_term}*
This will find packages whose names contain {search_term}. Similar to apt-cache search, but also shows whether a package is installed on your system by marking it with ii (installed) and un (not installed).
apt-cache show {package_name}
This command shows the description of package and other relevant information including version, size, dependencies and conflicts.
dpkg –print-avail {package_name}
This command is similar to “apt-cache show”.
dpkg -L {package_name}
This command will list files in package {package_name}.
dpkg -c foo.deb
This command lists files in the package “foo.deb”. Note that foo.deb is a pathname. Use this command on .deb packages that you have manually downloaded.
dlocate {package_name}
This command determines which installed package owns . It shows files from installed packages that match , with the name of the package they came from. Consider this to be a “reverse lookup” utility.
dpkg -S {package_name}
This command does the same as dlocate, but does not require the installation of any additional packages. It is slower than dlocate but has the advantage of being installed by default on all Debian and Ubuntu systems.
apt-file search {package_name}
This command acts like dlocate and dpkg -S, but searches all available packages. It answers the question, “what package provides this file?”.
apt-file needs to be updated regularly like apt-get. Use the command:
apt-file update
In order to use this command, the package apt-file must be installed on your system.
apt-cache pkgnames
This command provides a listing of every package in the system.
A general note on searching: If searching for a generates a list that is too long, you can filter your results by piping them through the command grep. Examples:
apt-cache search filename | grep -w filename
dpkg -L package | grep /usr/bin
For more information on apt-get, apt-cache and dpkg consult their manual pages by using the man command. These manuals will provide a wider scope of information in addition to all of the options that you can use with each program.
man apt-get
For more Linux Packagement tools go to:
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APT Packaging Management Tool In Detail; Linux
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