LDP/LDP/users/Jason-Evans/Package-Management-Basics.adoc

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= Package Management Basics: apt, yum, dnf, zypper, and pkg
==== Abstract
This guide is intended as a quick reference for the fundamentals of finding, installing, and upgrading packages on a variety of distributions, and should help you translate that knowledge between systems.
==== Audience
For those new to Linux who need a basic understanding of package management.
==== Original version of this doc
The original version of this guide can be found at https://www.digitalocean.com/community/tutorials/package-management-basics-apt-yum-dnf-pkg[Digital Ocean].
==== Revision History
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|=============================================================================
|15.1.2016 |v1.0 Converted and edited for TLDP |Jason Evans
|15.2.2016 |v1.1 Changed format to asciidoc and made corrections |Jason Evans
|=============================================================================
==== Contributions
* https://www.digitalocean.com/community/users/bpb[Brennen Bearnes]
(original author).
* http://wiki.tldp.org/Jason%20Evans[Jason Evans] (editor and maintainer for TLDP)
==== Feedback
Missing information, missing links, missing characters? Mail it to the maintainer of this document: jsevans _at_ youvegotthe.info
==== Copyright information
This work is licensed under a https://creativecommons.org/licenses/by-nc-sa/4.0/[Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License].
== 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 Packages in the stable release of a distribution may be out of date, especially where new or rapidly-changing software is concerned.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
--------------------------------------------
Most package systems are built around collections of package files. A package file is usually an archive which contains compiled binaries and other resources making up the software, along with installation scripts. Packages also contain valuable metadata, including their dependencies, a list of other packages required to install and run them.
While their functionality and benefits are broadly similar, packaging formats and tools vary by platform:
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|===========================================
|Operating System |Format |Tool(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, like Ubuntu, Linux Mint, and Raspbian, the package format is the .debfile. 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 supplanted by dnf, a modernized fork which retains most of yum's interface.
SuSE also uses RPM files. However, the package management software is known as zypper and has a tightly integrated GUI called YaST. Zypper's command line interface is very similar to yum and YasT can be access 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.
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|=========================================
|System |Command
|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.
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|=======================================================================
|System |Command |Notes
|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.
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|=======================================================================
|System |Command |Notes
|Debian / Ubuntu |`apt-cache search search_string` |
|CentOS |`yum search search_string` |
| |`yum search all search_string` |Searches all fields, including description.
|Fedora |`dnf search search_string` |
| |`dnf search all search_string` |Searches all fields, including description.
|SuSE |`zypper se search_string` |
|FreeBSD Packages |`pkg search search_string` |Searches by name.
| |`pkg search -f search_string` |Searches by name, returning full descriptions.
| |`pkg search -D search_string` |Searches description.
|FreeBSD Ports |`cd /usr/ports && make search name=package` |Searches by name.
| |`cd /usr/ports && make search key=search_string` |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.
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|=======================================================================
|System |Command |Notes
|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.
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|=======================================================================
|System |Command |Notes
|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.
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|=======================================================================
|System |Command |Notes
|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.
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|=======================================================================
|System |Command |Notes
|Debian / Ubuntu |`apt-get 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`|
|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 man:
----------
$ man page
----------
In man, you can navigate with the arrow keys. Press / to search for text within the page, and q to quit.
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|=======================================================================
|System |Command |Notes
|Debian / Ubuntu |`man apt-get` |Updating the local package database and working with packages.
| |`man apt-cache` |Querying the local package database.
| |`man dpkg` |Working with individual package files and querying
installed packages.
|CentOS |`man yum` |
|Fedora |`man dnf` |
|SuSE|`man zypper`|
|FreeBSD Packages |`man pkg` |Working with pre-compiled binary packages.
|FreeBSD Ports |`man ports` |Working with the Ports Collection.
|=======================================================================
Conclusion and Further Reading
------------------------------
This guide provides an overview of basic operations that can be
cross-referenced between systems, but only scratches the surface of a
complex topic. For greater detail on a given system, you can consult the
following resources:
1. https://www.digitalocean.com/community/tutorials/ubuntu-and-debian-package-management-essentials[This
guide] covers Ubuntu and Debian package management in detail.
2. There's an https://www.centos.org/docs/5/html/yum/[official CentOS guide to managing software with yum].
3. There's a https://fedoraproject.org/wiki/Dnf[Fedora wiki page about dnf], and an https://dnf.readthedocs.org/en/latest/index.html[official manual for dnf itself]
4. https://www.digitalocean.com/community/tutorials/how-to-manage-packages-on-freebsd-10-1-with-pkg[This guide] covers FreeBSD package management using pkg.
5. The https://www.freebsd.org/doc/handbook/[FreeBSD Handbook] contains
a https://www.freebsd.org/doc/handbook/ports-using.html[section on using
the Ports Collection].
6. http://doc.opensuse.org/documentation/html/openSUSE_114/opensuse-reference/cha.sw_cl.html[OpenSuSE documentation for Zypper] and http://doc.opensuse.org/documentation/html/openSUSE_114/opensuse-reference/cha.onlineupdate.you.html[YaST].