Introduction

Why was this document written?

Most modern Unix-like operating systems offer a centralized mechanism for finding and installing software. Software is usually distributed in the form of packages, kept in repositories. Working with packages is known as package management. Packages provide the basic components of an operating system, along with shared libraries, applications, services, and documentation.

A package management system does much more than one-time installation of software. It also provides tools for upgrading already-installed packages. Package repositories help to ensure that code has been vetted for use on your system, and that the installed versions of software have been approved by developers and package maintainers.

When configuring servers or development environments, it’s often necessary look beyond official repositories. Packages in the stable release of a distribution may be out of date, especially where new or rapidly-changing software is concerned. Nevertheless, package management is a vital skill for system administrators and developers, and the wealth of packaged software for major distributions is a tremendous resource.

What do you need?

This guide covers Debian, Ubuntu, CentOS, Fedora, SuSE, and FreeBSD and will require one of those distributions to be installed.

Note

All of the commands in this guide assume that the user is running the commands as root or with sudo.

Package Management Systems: A Brief Overview

In a Windows environment, programs are packaged in .exe or .msi installers which will then install most of the files needed to run the program. If your computer doesn’t have some dependant applications, then the program that you are trying to run will either not install or not run properly. You will then have to scour the internet in order to find the missing required applications or libraries. For example in CentOS 7, in order to install the VIM text editor, I need to add the following packages:

 gpm-libs                    x86_64      1.20.7-5.el7           base       32 k
 groff-base                  x86_64      1.22.2-8.el7           base      942 k
 perl                        x86_64      4:5.16.3-286.el7       base      8.0 M
 perl-Carp                   noarch      1.26-244.el7           base       19 k
 perl-Encode                 x86_64      2.51-7.el7             base      1.5 M
 perl-Exporter               noarch      5.68-3.el7             base       28 k
 perl-File-Path              noarch      2.09-2.el7             base       26 k
 perl-File-Temp              noarch      0.23.01-3.el7          base       56 k
 perl-Filter                 x86_64      1.49-3.el7             base       76 k
 perl-Getopt-Long            noarch      2.40-2.el7             base       56 k
 perl-HTTP-Tiny              noarch      0.033-3.el7            base       38 k
 perl-PathTools              x86_64      3.40-5.el7             base       82 k
 perl-Pod-Escapes            noarch      1:1.04-286.el7         base       50 k
 perl-Pod-Perldoc            noarch      3.20-4.el7             base       87 k
 perl-Pod-Simple             noarch      1:3.28-4.el7           base      216 k
 perl-Pod-Usage              noarch      1.63-3.el7             base       27 k
 perl-Scalar-List-Utils      x86_64      1.27-248.el7           base       36 k
 perl-Socket                 x86_64      2.010-3.el7            base       49 k
 perl-Storable               x86_64      2.45-3.el7             base       77 k
 perl-Text-ParseWords        noarch      3.29-4.el7             base       14 k
 perl-Time-HiRes             x86_64      4:1.9725-3.el7         base       45 k
 perl-Time-Local             noarch      1.2300-2.el7           base       24 k
 perl-constant               noarch      1.27-2.el7             base       19 k
 perl-libs                   x86_64      4:5.16.3-286.el7       base      687 k
 perl-macros                 x86_64      4:5.16.3-286.el7       base       43 k
 perl-parent                 noarch      1:0.225-244.el7        base       12 k
 perl-podlators              noarch      2.5.1-3.el7            base      112 k
 perl-threads                x86_64      1.87-4.el7             base       49 k
 perl-threads-shared         x86_64      1.43-6.el7             base       39 k
 vim-common                  x86_64      2:7.4.160-1.el7        base      5.9 M
 vim-filesystem              x86_64      2:7.4.160-1.el7        base      9.6 k
 which                       x86_64      2.20-7.el7             base       41 k

Imagine trying to manually install all of these programs one at a time just to be able to install a text editor! In the early days of Linux, we faced these kinds of problems, however this problem is fixed with package management systems such as apt, yum, and others. Package managers simplify everything. They look at the package that you want to install such as VIM, LibreOffice, etc., then look at what other package it depends upon, the dependencies of those packages, and so on; then it downloads them all and installs them. For example, in order to install VIM in CentOS 7 today, I simply have to run yum install vim.

Some different package management systems:

While their functionality and benefits are broadly similar, packaging formats and tools vary by platform:

Operating SystemFormatTool(s)

Debian

.deb

apt, apt-cache, apt-get, dpkg

Ubuntu

.deb

apt, apt-cache, apt-get, dpkg

CentOS

.rpm

yum

Fedora

.rpm

dnf

SuSE

.rpm

zypper

FreeBSD

Ports, .txz

make, pkg

In Debian and systems based on it such as Ubuntu, Linux Mint, and Raspbian, the package format is the .deb file. Apt, the Advanced Packaging Tool, provides commands used for most common operations: Searching repositories, installing collections of packages and their dependencies, and managing upgrades. APT commands operate as a front-end to the lower-level dpkg utility, which handles the installation of individual .deb files on the local system, and is sometimes invoked directly.

Fedora and enterprise level distributions like Red Hat Enterprise Linux (RHEL), CentOS, and Oracle Linux use RPM files. In CentOS, Oracle, and RHEL, yum is used to interact with both individual package files and repositories. In recent versions of Fedora, yum has been replaced by dnf, a modernized fork which retains most of yum’s functionality.

SuSE also uses RPM files. However, the package management software is known as zypper. Zypper’s command line interface is very similar to yum. SuSE also has a build-in gui called YasT that can handle package management and can be accessed from a graphical mode or from the command line.

FreeBSD’s binary package system is administered with the pkg command. FreeBSD also offers the Ports Collection, a local directory structure and tools which allow the user to fetch, compile, and install packages directly from source using Makefiles. It’s usually much more convenient to use pkg, but occasionally a pre-compiled package is unavailable, or syou may need to change compile-time options.

Update Package Lists

Most systems keep a local database of the packages available from remote repositories. It’s best to update this database before installing or upgrading packages. As a partial exception to this pattern, yum and dnf will check for updates before performing some operations, but you can ask them at any time whether updates are available.

SystemCommand

Debian / Ubuntu

apt-get update

CentOS

yum check-update

Fedora

dnf check-update

SuSE

zypper refresh

FreeBSD Packages

pkg update

FreeBSD Ports

portsnap fetch update

Upgrade Installed Packages

Making sure that all of the installed software on a machine stays up to date would be an enormous undertaking without a package system. You would have to track upstream changes and security alerts for hundreds of different packages. While a package manager doesn’t solve every problem you’ll encounter when upgrading software, it does enable you to maintain most system components with a few commands.

On FreeBSD, upgrading installed ports can introduce breaking changes or require manual configuration steps. It’s best to read /usr/ports/UPDATING before upgrading with portmaster.

SystemCommandNotes

Debian / Ubuntu

apt-get upgrade

Only upgrades installed packages, where possible.

 

apt-get dist-upgrade

May add or remove packages to satisfy new dependencies.

CentOS

yum update

 

Fedora

dnf upgrade

 

SuSE

zypper update

 

FreeBSD Packages

pkg upgrade

 

FreeBSD Ports

less /usr/ports/UPDATING

Uses less to view update notes for ports (use arrow keys to scroll, pressq to quit).

 

cd /usr/ports/ports-mgmt/portmaster && make install && portmaster -a

Installs portmaster and uses it to update installed ports.

Find a Package

Most distributions offer a graphical or menu-driven front end to package collections. These can be a good way to browse by category and discover new software. Often, however, the quickest and most effective way to locate a package is to search with command-line tools.

SystemCommandNotes

Debian / Ubuntu

apt-cache search

 

CentOS

yum search

 
 

yum search all

Searches all fields, including description.

Fedora

dnf search

 
 

dnf search all

Searches all fields, including description.

SuSE

zypper se

 

FreeBSD Packages

pkg search

Searches by name.

 

pkg search -f

Searches by name, returning full descriptions.

 

pkg search -D

Searches description.

FreeBSD Ports

cd /usr/ports && make search name=package

Searches by name.

 

cd /usr/ports && make search key=

Searches comments, descriptions, and dependencies.

View Info About a Specific Package

When deciding what to install, it’s often helpful to read detailed descriptions of packages. Along with human-readable text, these often include metadata like version numbers and a list of the package’s dependencies.

SystemCommandNotes

Debian / Ubuntu

apt-cache show package

Shows locally-cached info about a package.

 

dpkg -s package

Shows the current installed status of a package.

CentOS

yum info package

 
 

yum deplist package

Lists dependencies for a package.

Fedora

dnf info package

 
 

dnf repoquery -\/-requires package

Lists dependencies for a package.

SuSE

zypper info search string

Lists dependencies for a package.

FreeBSD Packages

pkg info package

Shows info for an installed package.

FreeBSD Ports

cd /usr/ports/category/port && cat pkg-descr

 

Install a Package from Repositories

Once you know the name of a package, you can usually install it and its dependencies with a single command. In general, you can supply multiple packages to install simply by listing them all.

SystemCommandNotes

Debian / Ubuntu

apt-get install package

 
 

apt-get install package1 package2

Installs all listed packages.

 

apt-get install -y package

Assumes "yes" where apt would usually prompt to continue.

CentOS

yum install package

 
 

yum install package1 package2

Installs all listed packages.

 

yum install -y package

Assumes "yes" where yum would usually prompt to continue.

Fedora

dnf install package

 
 

dnf install package1 package2

Installs all listed packages.

 

dnf install -y package

Assumes "yes" where dnf would usually prompt to continue.

SuSE

zypper install

 

FreeBSD Packages

pkg install package

 
 

pkg install package1 package2

Installs all listed packages.

FreeBSD Ports

cd /usr/ports/category/port && make install

Builds and installs a port from source.

Install a Package from the Local Filesystem

Sometimes, even though software isn’t officially packaged for a given operating system, a developer or vendor will offer package files for download. You can usually retrieve these with your web browser, or viacurl on the command line. Once a package is on the target system, it can often be installed with a single command.

On Debian-derived systems, dpkg handles individual package files. If a package has unmet dependencies, gdebi can often be used to retrieve them from official repositories.

On CentOS and Fedora systems, yum and dnf are used to install individual files, and will also handle needed dependencies.

SystemCommandNotes

Debian / Ubuntu

dpkg -i package.deb

 
 

apt-get install -yg debi && gdebi package.deb

Installs and uses gdebi to install package.deb and retrieve any missing dependencies.

CentOS

yum install package.rpm

 

Fedora

dnf install package.rpm

 

SuSE

zypper install package.rpm

 

FreeBSD Packages

pkg add package.txz

 
 

pkg add -f package.txz

Installs package even if already installed.

Remove One or More Installed Packages

Since a package manager knows what files are provided by a given package, it can usually remove them cleanly from a system if the software is no longer needed.

SystemCommandNotes

Debian / Ubuntu

apt-get remove package

yum remove package

 

apt-get autoremove

Removes unneeded packages.

CentOS

yum remove package

 

Fedora

dnf erase package

 

FreeBSD Packages

pkg delete package

 
 

pkg autoremove

Removes unneeded packages.

SuSE

zypper rm package

Removes unneeded packages.

FreeBSD Ports

pkg delete package

 
 

cd /usr/ports/path_to_port && make deinstall

De-installs an installed port.

Get Help

In addition to web-based documentation, keep in mind that Unix manual pages (usually referred to as man pages) are available for most commands from the shell. To read a page, use the man command. For example, man yum will give you a brief manual on how to use yum.