Candidates should be able to perform package management using the Debian package tools.
- Install, upgrade and uninstall Debian binary packages.
- Find packages containing specific files or libraries which may or may not be installed.
- Obtain package information like version, content, dependencies, package integrity, and installation status (Whether or not the package is installed).
- Awareness of apt.
Terms and Utilities
Concept of the package management system
Some people think that on GNU/Linux we have to compile all the software we need manually. This is not the case in 99% of cases and never has been the case in the last 20 years. GNU/Linux is the predecessor of what we call the App Store these days. All major distros do have huge archives of pre-compiled software called their repositories and some kind of a package manager software that takes care of searching these repositories, installing software from them, finding dependencies, installing them, resolving conflicts, and updating the system and installed software. Debian-based distros use
.deb files as their "packages" and use tools like
apt, and other tools to manage them.
Debian packages are names like
But where did this package come from? How does the OS know where to look for this deb package? The answer is Repositories. Each distro has its repository of packages. It can be on a Disk, A network drive, a collection of DVDs, or most commonly, a network address on the Internet.
On debian systems, the main configuration locations are:
[email protected]:~$ cat /etc/apt/sources.list #deb cdrom:[Ubuntu 22.04 LTS _Jammy Jellyfish_ - Beta amd64 (20220329.1)]/ jammy main restricted # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://us.archive.ubuntu.com/ubuntu/ jammy main restricted # deb-src http://us.archive.ubuntu.com/ubuntu/ jammy main restricted ## Major bug fix updates produced after the final release of the ## distribution. deb http://us.archive.ubuntu.com/ubuntu/ jammy-updates main restricted # deb-src http://us.archive.ubuntu.com/ubuntu/ jammy-updates main restricted ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in the universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://us.archive.ubuntu.com/ubuntu/ jammy universe # deb-src http://us.archive.ubuntu.com/ubuntu/ jammy universe deb http://us.archive.ubuntu.com/ubuntu/ jammy-updates universe # deb-src http://us.archive.ubuntu.com/ubuntu/ jammy-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free license. Please satisfy yourself as to ## your rights to use the software. Also, please note that the software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://us.archive.ubuntu.com/ubuntu/ jammy multiverse # deb-src http://us.archive.ubuntu.com/ubuntu/ jammy multiverse deb http://us.archive.ubuntu.com/ubuntu/ jammy-updates multiverse # deb-src http://us.archive.ubuntu.com/ubuntu/ jammy-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://us.archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse # deb-src http://us.archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse deb http://security.ubuntu.com/ubuntu jammy-security main restricted # deb-src http://security.ubuntu.com/ubuntu jammy-security main restricted deb http://security.ubuntu.com/ubuntu jammy-security universe # deb-src http://security.ubuntu.com/ubuntu jammy-security universe deb http://security.ubuntu.com/ubuntu jammy-security multiverse # deb-src http://security.ubuntu.com/ubuntu jammy-security multiverse # This system was installed using small removable media # (e.g. netinst, live or single CD). The matching "deb cdrom" # entries were disabled at the end of the installation process. # For information about how to configure apt package sources, # see the sources.list(5) manual.
Updating sources information:
This will check all the sources in the configs and update the information about the latest software available there.
This won't actually Upgrade the software. The Update will only Update the information about the packages and not the packages themselves.
Say you have heard about this amazing terminal multiplexer called
tmux and you want to give it a try.
$ tmux The program 'tmux' is currently not installed. You can install it by typing: sudo apt-get install tmux $ which tmux $ type tmux bash: type: tmux: not found
So let's install it. If it's in the repositories it's enough to tell the package manager to install it:
apt-get install tmux
- apt-get install asked for confirmation (Y)
- apt-get resolved dependencies, It knows what is needed to install this package and installs them
- Debian packages are something.deb
If you only want a dry-run/simulation:
apt-get install -s tmux
and this will only download the files needed into the cache without installing them:
apt-get install --download-only tmux
The downloaded packages are stored as a cache in
If you want to download only one specific package, you can do:
apt-get download tmux
Removing debian packages
apt-get remove tmux
And if you want to remove automatically installed dependencies:
$ apt-get autoremove tmux
$ apt-get autoremove Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED: linux-image-3.16.0-25-generic linux-image-extra-3.16.0-25-generic 0 upgraded, 0 newly installed, 2 to remove, and 0 not upgraded. After this operation, 203 MB of disk space will be freed. Do you want to continue? [Y/n] y
To autoremove whatever is not needed anymore.
- Removing a package will not remove its dependencies
- If removing a dependency, you'll get a warning about what will be removed alongside this package
Searching for packages
If you are using the apt suit, the search is done via
apt-cache or you can use the general
$ apt-cache search "tiny window" $ apt search grub2
For updating a single package:
apt-get install tzdata
And for upgrading whatever is installed:
Or going to a new distribution:
Note: like most other tools, you can configure the default configs at
/etc/apt/apt.conf and there is a program apt-config for this purpose.
Debian packages can have configuration actions that will take after the package is installed. This is done by
debconf. For example, tzdata will ask you about the timezone settings after you installed it. If you want to reconfigure a package that is already installed, you can use the
Package information with dpkg
The underlying tool to work with
.deb files is the
dpkg. It is your to-go tool if you want to do manual actions on a deb package. The general format is:
dpkg [OPTIONS] ACTION PACKAGE
Some common actions are:
|-c or --contents||Show the contents of a package|
|-C or --audit||Search for broken installed packages and propose solutions|
|--configure||Reconfigure an installed package|
|-i or --install||Install or Upgrade a package; Wont resolve / install dependencies|
|-I or --info||Show Info|
|-l or --list||List all installed pckages|
|-L or --listfiles||List all files related to this package|
|-P or --purge||Remove the package and its configuration files|
|-r or --remove||Remove the package; Keep the configurations|
|-s or --status||Display status of a package|
|-S or --search||Search and see which package owns this file|
You can check the contents:
jadi@lpicjadi:/tmp$ dpkg --contents bzr_2.7.0+bzr6622+brz_all.deb drwxr-xr-x root/root 0 2019-09-19 18:25 ./ drwxr-xr-x root/root 0 2019-09-19 18:25 ./usr/ drwxr-xr-x root/root 0 2019-09-19 18:25 ./usr/share/ drwxr-xr-x root/root 0 2019-09-19 18:25 ./usr/share/doc/ drwxr-xr-x root/root 0 2019-09-19 18:25 ./usr/share/doc/bzr/ -rw-r--r-- root/root 404 2019-09-19 18:25 ./usr/share/doc/bzr/NEWS.Debian.gz -rw-r--r-- root/root 1301 2019-09-19 18:25 ./usr/share/doc/bzr/changelog.gz -rw-r--r-- root/root 1769 2019-09-19 18:25 ./usr/share/doc/bzr/copyright
Or install a deb package (without its dependencies) or check its status:
$ dpkg -s bzr Package: bzr Status: deinstall ok config-files Priority: optional Section: vcs Installed-Size: 102 Maintainer: Ubuntu Developers <[email protected]> Architecture: all Version: 2.6.0+bzr6595-1ubuntu1 Config-Version: 2.6.0+bzr6595-1ubuntu1 Depends: python-bzrlib (<= 2.6.0+bzr6595-1ubuntu1.1~), python-bzrlib (>= 2.6.0+bzr6595-1ubuntu1), python:any Recommends: python-gpgme Suggests: bzr-doc, bzrtools, python-bzrlib.tests Breaks: bzr-pqm (<< 1.4.0~bzr80), bzr-xmloutput (<< 0.8.8+bzr160), python-bzrlib (<< 2.4.0~beta3~) Conffiles: /etc/bash_completion.d/bzr b8d9ca95521a7c5f14860e205a854da2 Description: easy to use distributed version control system Bazaar is a distributed version control system designed to be easy to use and intuitive, able to adapt to many workflows, reliable, and easily extendable. . Publishing of branches can be done over plain HTTP, that is, no special software is needed on the server to host Bazaar branches. Branches can be pushed to the server via sftp (which most SSH installations come with), FTP, or over a custom and faster protocol if bzr is installed in the remote end. . Merging in Bazaar is easy, as the implementation can avoid many spurious conflicts deals well with repeated merges between branches, and can handle modifications to renamed files correctly. . Bazaar is written in Python and has a flexible plugin interface that can be used to extend its functionality. Many plugins exist, providing useful commands (bzrtools), graphical interfaces (qbzr), or native interaction with Subversion branches (bzr-svn). . Install python-paramiko if you are going to push branches to remote hosts with sftp, and python-pycurl if you'd like SSL certificates always to be verified. Homepage: http://bazaar-vcs.org Original-Maintainer: Debian Bazaar Maintainers <[email protected]>
Or even purge an installed package; Removing the package and all of its configurations. To Purge a package, use the -P or --purge switch.
There is also -L to check the files and directories a package installed:
$ dpkg -L bzr /. /usr /usr/bin /usr/bin/jcal /usr/share /usr/share/doc /usr/share/doc/jcal /usr/share/doc/jcal/README /usr/share/doc/jcal/copyright /usr/share/man /usr/share/man/man1 /usr/share/man/man1/jcal.1.gz /usr/share/doc/jcal/changelog.Debian.gz
and -S will show which package installed the given file:
$ dpkg -S /var/lib/mplayer/prefs/mirrors mplayer: /var/lib/mplayer/prefs/mirrors
Common apt-get options
|autoclean||Removes unused packages|
|check||Check db for issues|
|clean||Clean the DB, you can do a
|dist-upgrade||Checks for new versions of the OS; Major upgrade|
|install||Install or upgrade packages|
|remove||Removes a package|
|source||Install the source of a package|
|update||Updates the information about packages from repositories|
|upgrade||Upgrades all packages|
In some cases a package is installed but without proper dependencies (say using
dpkg) or an installation is interrupted for any reason. In these cases a
apt-get install -fmight help,
Common apt-cache options
|pkgnames||Shows all installed packages|
|showpkg||Show information about a package|
|unmet||Show unmet dependencies for all installed packages or the one you specified|
There are even more tools, the tools with fancy GUIs or text-based tools and user interface tools like
|← 102.3 Manage shared libraries||102.5 Use RPM and YUM package management →|