Apt get commands linux

apt-get command in Linux with Examples

apt-get is a command-line tool which helps in handling packages in Linux. Its main task is to retrieve the information and packages from the authenticated sources for installation, upgrade and removal of packages along with their dependencies. Here APT stands for the Advanced Packaging Tool.

Syntax:

Most Used Commands: You need to provide one of the commands below, if -h option is not used.

• update : This command is used to synchronize the package index files from their sources again. You need to perform an update before you upgrade or dist-upgrade.
• upgrade : This command is used to install the latest versions of the packages currently installed on the user’s system from the sources enumerated in /etc/apt/sources.list . The installed packages which have new packages available are retrieved and installed. You need to perform an update before the upgrade, so that apt-get knows that new versions of packages are available.
• dselect-upgrade : This is used alongwith the Debian packaging tool, dselect . It follows the changes made by dselect to the Status field of available packages, and performs any actions necessary to realize that state.
• dist-upgrade : This command performs the function of upgrade, and also handles changing dependencies with new versions of packages. If necessary, the apt-get command will try to upgrade important packages at the expense of less important ones. It may also remove some packages in this process.
• install : This command is used to install or upgrade packages. It is followed by one or more package names the user wishes to install. All the dependencies of the desired packages will also be retrieved and installed. The user can also select the desired version by following the package name with an ‘equals’ and the desired version number. Also, the user can select a specific distribution by following the package name with a forward slash and the version or the archive name (e.g. ‘stable’, ‘testing’ or ‘unstable’). Both of these version selection methods have the potential to downgrade the packages, so must be used with care.
• remove : This is similar to install , with the difference being that it removes the packages instead of installing. It does not remove any configuration files created by the package.
• purge : This command removes the packages, and also removes any configuration files related to the packages.
• check : This command is used to update the package cache and checks for broken dependencies.
• download : This command is used to download the given binary package in the current directory.

Options:

• –no-install-recommends : By passing this option, the user lets apt-get know not to consider recommended packages as a dependency to install.
• –install-suggests : By passing this option, the user lets apt-get know that it should consider suggested packages as dependencies to install.
• -d or –download-only : By passing this option, the user specifies that apt-get should only retrieve the packages, and not unpack or install them.
• -f or –fix-broken : By passing this option, the user specifies that apt-get should attempt to correct the system with broken dependencies in place.
• -m or –ignore-missing or –fix-missing : By passing this option, the user specifies that apt-get should ignore the missing packages ( packages that cannot be retrieved or fail the integrity check ) and handle the result.
• –no-download : By passing this command, the user disables downloading for apt-get. It means that it should only use the .debs it has already downloaded.
• -q or –quiet : When this option is specified, apt-get produces output which is suitable for logging.
• -s or –simulate or –just-print or –dry-run or –recon or –no-act : This option specifies that no action should be taken, and perform a simulation of events that would occur based on the current system, but do not change the system.
• -y or –yes or –assume-yes : During the execution of apt-get command, it may sometimes prompt the user for a yes/no. With this option, it is specified that it should assume ‘yes’ for all prompts, and should run without any interaction.
• –assume-no : With this option, apt-get assumes ‘no’ for all prompts.
• –no-show-upgraded : With this option, apt-get will not show the list of all packages that are to be upgraded.
• -V or –verbose-versions : With this option, apt-get will show full versions for upgraded and installed packages.
• –show-progress : With this option, apt-get will show user-friendly progress in the terminal window when the packages are being installed, removed or upgraded.
• -b or –compile or –build : With this option, apt-get will compile/build the source packages it downloads.
• –no-upgrade : With this option, apt-get prevents the packages from being upgraded if they are already installed.
• –only-upgrade : With this option, apt-get will only upgrade the packages which are already installed, and not install new packages.
• –reinstall : With this option, apt-get reinstalls the packages that are already installed, at their latest versions.
• –auto-remove or –autoremove : When using apt-get with install or remove command, this option acts like running the autoremove command.
• -h or –help : With this option, apt-get displays a short usage summary.

Output:

-v or –version : With this option, apt-get displays it’s current version number.

Output:

Note: apt-get command will return 0 for successful executions, and decimal 100 in case of errors.

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Ubuntu Documentation

This article applies to all supported versions of Ubuntu

Package management via apt-get runs hand-in-hand with the /etc/apt/sources.list file. For information on editing or updating your sources list see SourcesList.

Introduction

This page describes how to handle the packages on your system using apt-get and related commands. For example, you can install a new package, remove an installed package, or update all installed packages to the latest versions.

Commands

All these commands except the search commands must be run as root or with superuser privileges, see sudo for more information.

Example:

Installation commands

This command installs a new package.

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 is an Ncurses viewer of packages installed or available. Aptitude can be used from the command line in a similar way to apt-get. Enter man aptitude for more information.
APT and aptitude will accept multiple package names as a space delimited list. For example:

Use the -s flag to simulate an action. For example: «apt-get -s install

» will simulate installing the package, showing you what packages will be installed and configured.

auto-apt

This command runs under the control of auto-apt. If a program tries to access a file known to belong in an uninstalled package, auto-apt will install that package using apt-get. This feature requires apt and sudo to work.

Auto-apt keeps databases which need to be kept up-to-date in order for it to be effective. This is achieved by calling the commands auto-apt update, auto-apt updatedb and auto-apt update-local.

Usage example

You’re compiling a program and, all of a sudden, there’s an error because it needs a file you don’t have. The program auto-apt asks you to install packages if they’re needed, stopping the relevant process and continuing once the package is installed. It will then ask to install the needed packages and call apt-get automatically. If you’re running X, a graphical interface will replace the default text interface.

Maintenance commands

Run this command after changing /etc/apt/sources.list or /etc/apt/preferences . For information regarding /etc/apt/preferences, see PinningHowto. 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.

This command upgrades all installed packages. This is the equivalent of «Mark all upgrades» in Synaptic.

The same as the above, except add the «smart upgrade» checkbox. 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 dist-upgrade» does not upgrade from a previous version of Ubuntu. For more information of upgrading from a previous version of Ubuntu see http://www.ubuntu.com/getubuntu/upgrading .

This command does the same thing as Edit->Fix Broken Packages in Synaptic. Do this if you get complaints about packages with «unmet dependencies».

This 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.

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 will tell you how much space cached packages are consuming.

Reconfigure the named package. With many packages, you’ll be prompted with some configuration questions you may not have known were there.

For example: will present you with a «wizard» on configuring fonts in Ubuntu.

This command places the desired package on hold. TODO: Bug #42178: This is the same as Synaptic’s Package->Lock Version. */

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.

Removal commands

• This command removes an installed package, leaving configuration files intact.
• This command completely removes a package and the associated configuration files. Configuration files residing in

are not usually affected by this command.

+ operator

If you want to remove package1 and install package2 in one step: .

This command removes packages that were installed by other packages and are no longer needed.

• 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.

Search commands

Each package has a name and a description. This command lists packages whose name or description contains .

This will find packages whose names contain . 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).

This command shows the description of package

and other relevant information including version, size, dependencies and conflicts.
This command is similar to «apt-cache show».

This command will list files in package

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.

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.

In order to use this command, the package dlocate must be installed on your system.

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.

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:

In order to use this command, the package apt-file must be installed on your system.

A general note on searching: If searching generates a list that is too long, you can filter your results by piping them through the command grep. Examples:

will show only the files that contain as a whole word

will list files located in the directory /usr/bin, useful if you’re looking for a particular executable.

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.

Example: .

Typical usage example

I want to feel the wind in my hair, I want the adrenaline of speed. So let’s install a racing game. But what racing games are available?

It gives me a lot of answers. I see a game named «torcs». Let’s get some more information on this game.

Hmmm. it seems interesting. But is this game not already installed on my computer? And what is the available version? Which repository is it from (Universe or Main)?

Ok, so now, let’s install it!

What is the command I must type in the console to launch this game? In this example, it’s straightforward («torcs»), but that’s not always the case. One way of finding the name of the binary is to look at what files the package has installed in «/usr/bin». For games, the binary will be in «/usr/games». For administrative programs, it’s in «/usr/sbin».

The first part of the command display all files installed by the package «torcs» (try it). With the second part, we ask to only display lines containing «/usr/games/».

Hmmm, that game is cool. Maybe there are some extra tracks?

But I’m running out of space. I will delete the apt cache!

Oh no, my mother asked me to remove all games from this computer. But I want to keep the configuration files so I can simply re-install it later.

If I want to also remove config files :

Setting up apt-get to use a http-proxy

These are three methods of using apt-get with a http-proxy.

Temporary proxy session

This is a temporary method that you can manually use each time you want to use apt-get through a http-proxy. This method is useful if you only want to temporarily use a http-proxy.

Enter this line in the terminal prior to using apt-get (substitute your details for yourproxyaddress and proxyport).

If you normally use sudo to run apt-get you will need to login as root first for this to work unless you also add some explicit environment settings to /etc/sudoers, e.g.

APT configuration file method

This method uses the apt.conf file which is found in your /etc/apt/ directory. This method is useful if you only want apt-get (and not other applications) to use a http-proxy permanently.

On some installations there will be no apt-conf file set up. This procedure will either edit an existing apt-conf file or create a new apt-conf file.

Add this line to your /etc/apt/apt.conf file (substitute your details for yourproxyaddress and proxyport).

Save the apt.conf file.

BASH rc method

This method adds a two lines to your .bashrc file in your $HOME directory. This method is useful if you would like apt-get and other applications for instance wget, to use a http-proxy.

Add these lines to the bottom of your

/.bashrc file (substitute your details for yourproxyaddress and proxyport)

Save the file. Close your terminal window and then open another terminal window or source the

Test your proxy with sudo apt-get update and whatever networking tool you desire. You can use firestarter or conky to see active connections.

If you make a mistake and go back to edit the file again, you can close the terminal and reopen it or you can source

/.bashrc as shown above.

How to login a proxy user

If you need to login to the Proxy server this can be achieved in most cases by using the following layout in specifying the proxy address in http-proxy. (substitute your details for username, password, yourproxyaddress and proxyport)

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