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Package Management

Updated Dec 30, 2021 ·

Package Managers​

In Linux, package managers are essential tools for installing, updating, and managing software. Each Linux distribution has its own package management system, tailored to handle its specific needs and software ecosystem.

Ubuntu and Debian:

  • apt-get
  • dpkg
  • aptitude
  • dselect

RHEL and CentOS:

  • yum
  • rpm

Using apt-get​

apt-get is a command-line tool for handling packages, providing a straightforward way to install, update, and remove software.

To install a package:

sudo apt-get install -y <package>

To view repositories:

cat /etc/apt/sources.list

To update repositories:

sudo apt-get update

To search for a package in the cache:

apt-cache search <package>

To clean up packages:

sudo apt-get clean

To clean up packages that are no longer available:

sudo apt-get autoclean

To simulate installation:

sudo apt-get install -s -y <package>

To download source file of a package:

apt-get source <package>

To upgrade installed packages:

sudo apt-get upgrade

To update the kernel for the specific distro:

sudo apt-get dist-upgrade

To display statistics about available packages:

apt-cache stats

To query a package's dependencies:

apt-cache depends <package>

To list package names available in the repository:

apt-cache pkgnames

To count available packages:

apt-cache pkgnames | wc -l

To list packages with unmet dependencies:

apt-cache unmet

Using dpkg​

dpkg or the Debian package manager is used to install, remove, and provide information about .deb packages.

  1. Download .deb file from link by:

    wget <link>

  2. Get package from .deb file by:

    dpkg -i app.deb

    NOTE: this may fail if app have some dependencies. If it fails, dependencies are registered as NEEDED TO BE FIXED

  3. Do an update:

    apt-get update -year

  4. Upgrade and install registered dependencies:

    apt-get -f upgrade

To display all installed packages:

dpkg --get-selections

To display all files installed for a package:

dpkg -L <package>

To remove a package (excluding configuration files):

dpkg --remove <package>

To remove a package including configuration files:

dpkg --purge <package>

Using aptitude​

aptitude is a high-level interface to the package manager, offering a text-based user interface as well as command-line capabilities.

To check if aptitude is installed:

which aptitude

To search for aptitude in repositories:

apt-get update
apt-cache search aptitude

To install a package with aptitude:

aptitude install <package>

To open aptitude GUI:

aptitude

# to open GUI                         aptitude 
#   to navigate                         ?
#   to go back/existing                 q

Using dselect​

dselect is an older interface for managing packages, now largely obsolete but still available. To use dselect, follow these steps:

  1. Install dselect (if not already installed):

    sudo apt-get install dselect

  2. Run dselect:

    sudo dselect

  3. Navigate through the interface to update the package list, select packages for installation or removal, and apply changes.

While dselect provides a comprehensive interface for package management, it is largely considered obsolete and has been replaced by more modern tools like aptitude and apt.

Using yum​

yum​

yum is the default package manager for RHEL and CentOS, used to install, update, and remove packages as well as manage repositories.

To see all installed packages:

yum list installed

To install a package:

sudo yum install -y <package>

To search if a package is available in repositories:

yum search <package>

To check repositories:

ls /etc

To update packages:

sudo yum update -y

To upgrade packages:

sudo yum upgrade -y

To list all repositories:

ll /etc/yum.repos.d

To check if updates are available:

yum check-update

To check updates for a specific package:

yum check-update http

To remove a package:

yum remove -y <package>

To list repositories:

yum repolist
yum repolist all

To display info about a package:

yum list <package>

To display more info about a package:

yum info <package>

To get a list of dependencies of a package:

yum deplist <package>

To clean packages:

yum clean packages

To clean all:

yum clean all

yumdownloader​

yumdownloader is a command-line utility for downloading RPM packages from the YUM repositories without installing them. It is particularly useful when you need to obtain specific files from a package or wish to store the RPM for later use.

To download a package:

yumdownloader <package>

To resolve dependencies and download:

yumdownloader --resolve <package>

To extract and send to standard output:

rpm2cpio <full-package-name>

To view contents:

rpm2cpio <package.rpm> | cpio -t

To extract and redirect output to a file:

rpm2cpio <package.rpm> > <filename>

yum modules​

The yum module command is used to manage module properties:

Got it! Here are the commands with their descriptions preceding the code blocks:

  • List all available modules:

    yum module list

  • Search for the module that provides httpd:

    yum module provides httpd

  • Display detailed information about the PHP module:

    yum module info php

  • Show profiles for the PHP module:

    yum module info --profile php

  • Show which streams are available for the PHP module:

    yum module list php

  • Install the PHP 7.1 module stream:

    yum module install php:7.1
    yum install @php:7.1

  • Install a specific profile within the PHP 7.1 module stream:

    yum module install php:7.1/devel

  • Install httpd and automatically enable its module stream:

    yum install httpd

  • Enable the PHP 7.1 module stream without installing it:

    yum module enable php:7.1

  • Install a specific PHP module stream (e.g., PHP 7.1):

    yum module install php:7.1

  • Update to the newer PHP 7.2 module stream:

    yum module install php:7.2

  • Update or downgrade packages from a previous module stream that are not listed in installed profiles:

    yum distro-sync

yum groups​

To list grouped packages:

yum grouplist | more

Using rpm​

The rpm (Red Hat Package Manager) command is used for managing packages on Red Hat-based systems such as RHEL and CentOS. It allows you to install, update, query, verify, and remove packages. Unlike other package managers, rpm does not handle dependencies, so you might need to resolve them manually.

  • Package contains an archive of files that is compressed with cpio, as well of metadata and a list of package dependencies.
  • RPM packages may contain scripts as well.
  • To install packages, repositorues are used.
  • Individual packages may be installed, but this should be avoided.

To download and install a package using rpm:

wget https://downloads.redhat.com/redhat/rhel/rhel-8-beta/baseos/x86_64/Packages/nano-2.9.8-1.el8.x86_64.rpm
rpm -i nano-2.9.8-1.el8.x86_64.rpm
rpm -ivh nano-2.9.8-1.el8.x86_64.rpm  # Optional with progress and verbose

Setting Up Repository Access​

Listing and Adding Repos​

To see all repositories:

sudo dnf repolist

To see the directory listing:

ll /etc/yum.repos.d/

To create a new repository entry:

sudoedit /etc/yum.repos.d/newapp.repo

[appname]
name=Name of the application 
mirrorlist=https://place-url-here
baseurl=https://place-mirrorlist-here
enabled=0

Modules and Application Streams​

RHEL8 introduces application streams and modules to enhance package management.

  • Application streams separate user space packages from core kernel operations
  • Base packages are provided through the BaseOS repository
  • Appstream is provided as a separate repository

Modules

  • Application streams are delivered in 2 formats
    • traditional RPMs
    • new modules
  • Modules can contain streams to make multiple versions of applications availble
  • Enabling a module stream gives access to RPM packages in that stream
  • Modules can also have profiles - a list of packages that belong to a specific use-case
  • The package list of a module can contain packages outside the module stream
  • You can use the yum module to manage modules

rpm Commands​

rpm queries by default are against the database of installed packages, add '-p' to query package files.

  • rpm is the legacy command to manage RPM packages.
  • DO NOT USE rpm as it doesn't consider other dependencies.
  • However, it is usefule for performing package queries .

Query the RPM database to check if the specified package is installed. It returns the package name and version if found.

rpm -q <package>

Display detailed information about the specified installed package, including the name, version, release, size, and a description.

rpm -qi <package>

List all files installed by the specified package.

rpm -q --list <package>
rpm -ql <package>

List all installed packages in the order they were installed, with the most recently installed packages listed first.

rpm -qa --last

Display the dependencies required by the specified RPM package file (not the installed package).

rpm -qpR <pkg-name>

Rebuild the RPM database. This can be useful if the database is corrupted.

rpm --rebuilddb

List all documentation files for the specified installed package.

rpm -qdf <path-to-package>

Verify all installed packages against their RPM database entries. It checks file sizes, permissions, types, owners, groups, and MD5 checksums.

rpm -Va

Installing a package using the RPM file.

# -ivh vsersus -Uvh
# i means install package
# U means update package
# If package doesnt exist, -Uvh installs package
# If package exists, -Uvh updates the current package
rpm -Uvh <package.rpm>

Red Hat Subscription Manager​

Red Hat Subscription Manager (RHSM) is a tool that helps manage system entitlements and subscriptions for Red Hat products. It provides an interface for registering systems, attaching subscriptions, and managing repositories, ensuring that your systems have access to the necessary software and updates.

Key Features​

  1. System Registration:

    • Register your system with Red Hat to gain access to subscriptions and repositories.
    • Ensure compliance and receive the latest updates and patches.

  2. Subscription Management:

    • Attach and manage subscriptions to ensure that the system is entitled to the correct Red Hat products.
    • View and manage the details of your subscriptions.

  3. Repository Management:

    • Enable and disable repositories to control which packages are available for installation.
    • Customize the repositories based on your subscription entitlements.

Common Commands​

  • Register a system with Red Hat:

    sudo subscription-manager register --username=<your-username> --password=<your-password>

  • With an activation key:

    sudo subscription-manager register --activationkey=<activation-key> --org=<organization-id>

  • List available subscriptions:

    sudo subscription-manager list --available

  • Attach a subscription to the system:

    sudo subscription-manager attach --pool=<pool-id>

  • Remove a subscription from the system:

    sudo subscription-manager remove --serial=<serial-number>

  • List consumed subscriptions:

    sudo subscription-manager list --consumed

Managing Repositories​

  • List all available repositories:

    sudo subscription-manager repos --list

  • Enable a repository:

    sudo subscription-manager repos --enable=<repo-id>

  • Disable a repository:

    sudo subscription-manager repos --disable=<repo-id>

Examples​

  1. Registering a System:

    sudo subscription-manager register --username=johndoe --password=password123

  2. Attaching a Subscription:

    sudo subscription-manager attach --pool=8a85f9833e8b4e37013e8b4e38e9001a

  3. Enabling a Repository:

    sudo subscription-manager repos --enable=rhel-7-server-rpms

  4. Listing Consumed Subscriptions:

    sudo subscription-manager list --consumed