Managing Software Packages on Linux

The Advanced Package Tool (APT) is a free collection of pre-installed tools that simplify the process of installing, upgrading, configuring, and removing software packages on Linux distributions.

APT relies on package repositories, which are collections of software packages maintained by the distribution's community or organization, located on remote servers.

Searching for packages

To search for a software package on the APT registries that partially matches a specified keyword, you can use the apt search command:

$ apt search term

Where term is a regular expression such as tree or tree$.

On the other hand, to perform an exact search, you can use the following syntax:

$ apt search '^term$'

Which in regex translates to: "the package name starts and ends with the specified term".

Upon execution, the apt command will perform a linear, lexically-ordered search through the available packages in APT repositories and output the name and short description of each package matching the specified regex.

Example

This command will output all the packages containing the term tree in their name:

$ apt search tree
Sorting... Done
Full Text Search... Done
tre-command/jammy 0.3.6-2 amd64
  Tree command, improved

tree/jammy 2.0.2-1 amd64
  displays an indented directory tree, in color

tree-ppuzzle/jammy 5.3~rc16+dfsg-9 amd64
  Parallelized reconstruction of phylogenetic trees by maximum likelihood

tree-puzzle/jammy 5.3~rc16+dfsg-9 amd64
  Reconstruction of phylogenetic trees by maximum likelihood

tree-puzzle-doc/jammy 5.3~rc16+dfsg-9 all
  Reconstruction of phylogenetic trees by maximum likelihood (doc)

treeline/jammy 3.1.4-1 all
  versatile tree-like structured custom data manager

This command will only output the package whose exact name is tree:

$ apt search '^tree$'
Sorting... Done
Full Text Search... Done
tree/jammy 2.0.2-1 amd64
  displays an indented directory tree, in color

Showing package information

To get additional information about a package, such as its latest available version number, maintainer list, size, dependency list, and more, you can use the apt show command:

$ apt show package

Where package is the exact name of the package.

Example

This command will output detailed information about the tree package:

$ apt show tree
Package: tree
Version: 2.0.2-1
Priority: optional
Section: universe/utils
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Florian Ernst <florian@debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 116 kB
Depends: libc6 (>= 2.34)
Homepage: http://mama.indstate.edu/users/ice/tree/
Task: xubuntu-desktop, lubuntu-desktop, ubuntu-mate-core, ubuntu-mate-desktop, ubuntu-budgie-desktop, ubuntu-budgie-desktop-raspi
Download-Size: 47.9 kB
APT-Sources: http://archive.ubuntu.com/ubuntu jammy/universe amd64 Packages
Description: displays an indented directory tree, in color

Installing packages

To install one or more packages, including any additional packages they depend on in order to function properly, you can use the apt install command:

$ sudo apt install package ...

Where package ... is a list of package names separated by a space character.

Notes:

• This command requires sudo privileges to run, as regular users don't have permission to install system-wide packages.

• Before installing packages, make sure to update the index with the latest packages information using the sudo apt update command.

Example

This command will first update the index:

$ sudo apt update
Get:1 http://security.ubuntu.com/ubuntu jammy-security InRelease [129 kB]
Hit:2 http://archive.ubuntu.com/ubuntu jammy InRelease
Get:3 http://archive.ubuntu.com/ubuntu jammy-updates InRelease [128 kB]
Hit:4 http://archive.ubuntu.com/ubuntu jammy-backports InRelease
Get:5 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages [2602 kB]
Get:6 http://archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages [1448 kB]
Fetched 4307 kB in 1s (7798 kB/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done

This command will install the latest available version of the tree package:

$ sudo apt install tree
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
  tree
0 upgraded, 1 newly installed, 0 to remove and 28 not upgraded.
Need to get 47.9 kB of archives.
After this operation, 116 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu jammy/universe amd64 tree amd64 2.0.2-1 [47.9 kB]
Fetched 47.9 kB in 0s (738 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package tree.
(Reading database ... 14364 files and directories currently installed.)
Preparing to unpack .../tree_2.0.2-1_amd64.deb ...
Unpacking tree (2.0.2-1) ...
Setting up tree (2.0.2-1) ...
Processing triggers for man-db (2.10.2-1) ...

Installing a specific package version

To check the available versions of a package, you can use the apt list command:

$ apt list -a package

To install a specific package version instead of the latest default version, you can use the apt install command with the following syntax:

$ sudo apt install package=version ...

Where:

• package is the name of the package.
• version is the version number of the package.

Example

This command will output the list of available versions of the mysql-client package:

$ apt list -a mysql-client
Listing... Done
mysql-client/jammy-updates,jammy-security 8.0.39-0ubuntu0.22.04.1 all
mysql-client/jammy 8.0.28-0ubuntu4 all

This command will install the mysql-client package at version 8.0.28-0ubuntu4:

$ sudo apt install mysql-client=8.0.28-0ubuntu4
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
  mysql-client
0 upgraded, 1 newly installed, 0 to remove and 27 not upgraded.
Need to get 9414 B of archives.
After this operation, 111 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu jammy/main amd64 mysql-client all 8.0.28-0ubuntu4 [9414 B]
Fetched 9414 B in 0s (31.3 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package mysql-client.
(Reading database ... 14360 files and directories currently installed.)
Preparing to unpack .../mysql-client_8.0.28-0ubuntu4_all.deb ...
Unpacking mysql-client (8.0.28-0ubuntu4) ...
Setting up mysql-client (8.0.28-0ubuntu4) ...

Upgrading packages

To upgrade a package to a greater or latest version, you can use the apt install command:

$ sudo apt install package[=version] ...

Alternatively, you can use the apt upgrade command to upgrade all installed packages to their latest version at once:

$ sudo apt upgrade

Notes:

• Before upgrading packages, make sure to update the index with the latest packages information using the sudo apt update command.
• This command will also upgrade the package dependencies to their latest version.

Uninstalling packages

To uninstall packages, you can use the apt remove command:

$ sudo apt remove package ...

Alternatively, to uninstall packages including their dependencies, you can use the apt purge command:

$ sudo apt purge package ...

Example

This command will remove the tree package:

$ apt remove tree
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages will be REMOVED:
  tree
0 upgraded, 0 newly installed, 1 to remove and 28 not upgraded.
After this operation, 116 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 14372 files and directories currently installed.)
Removing tree (2.0.2-1) ...
Processing triggers for man-db (2.10.2-1) ...

Note: When prompted with the question "Do you want to continue? [Y/n]", type y and press ENTER to confirm the package deletion.

Removing unused dependencies

To remove all dependencies that are no longer required by any package on the system, you can use the apt autoremove command:

$ sudo apt autoremove

Summary

Here's a summary of what you've learned in this lesson:

• The apt search command is used to search for available packages on the APT repositories.
• The apt show command is used to retrieve information about a package.
• The apt install command is used to install packages on the system.
• The apt list -a command is used to list all available versions of a package.
• The apt update command is used to update the APT index.
• The apt upgrade command is used to upgrade packages to a greater version (if available).
• The apt remove command is used to uninstall packages from the system.
• The apt purge command is used to uninstall packages and their dependencies from the system.
• The apt autoremove command is used to uninstall unused dependencies from the system.