Red Hat uses RPM and Yum package management systems. RPM allows installing individual packages through command line tools while Yum manages packages from repositories, resolving dependencies automatically. Key commands for RPM include rpm to install, upgrade, and remove packages. Yum commands like yum install and yum update access Red Hat repositories to manage packages on the system. Additional repositories can be configured to access packages beyond the default repositories.

1. Package Management in
Red Hat

2. Package Management
• Software is the basis of any operating system, allowing you to install and
use different utilities.
• In Linux, software is distributed through the use of packages, which
contain the actual software files.
• Each distribution of Linux has its own package management system.
• For Red Hat, there are two package management systems: RPM and Yum
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3. Working with RPM
• A package contains a directory structure that is composed of files to make up
the software application.
• In Red Hat, packages have the .rpm extension and can be installed through
different means.
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4. Naming Convention RPM
• Package Syntax: package_name-version-release.arch.rpm
• As an example, let’s look at the postfix package, which is used to install an SMTP
mail server:
• postfix-2.6.6-2.el6.x86_64.rpm
• Name of this package is postfix, the version number is 2.6.6, and it is meant for a
64-bit operating system.
• The -2 is the release, and the el6 is something you find only in Red Hat packages
because it specifies an internal version number for the Red Hat release.
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5. Package Dependency
• Sometimes for an installation it requires to install another as well; this is known
as a dependency.
• Certain packages require certain versions to make sure that their dependencies
don’t break when upgrading.
• You can see why being able to get version information from packages is a
necessary skill.
• All packages are held within a repository somewhere, depending on who
produces the package.
• Red Hat has its own software repositories, which hold the packages for the Red
Hat operating system.
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6. Installing and Removing Packages
• RPM is the utility is used to manage individual packages outside the repositories.
• Used to install .rpm packages that are downloaded (either manually from the
repositories or the Web).
• Syntax: rpm [options]
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7. RPM Options 7
The options for rpm are divided into three different sections
(modes): install/upgrade/erase, query, and verify.

8. RPM Options 8

9. Downloading an RPM 9
To download something from the command line, use the wget
command.
Step 1. Download the nano package from the Web:
# wget http://www.nano-editor.org/dist/v2.2/RPMS/nano-2.2.6-
1.x86_64.rpm
Step 2. When the download is finished, the package is in the present
working directory.
Install it with the rpm command:
# rpm -ivh nano-2.2.6-1.x86_64.rpm

10. Issue in RPM 10

11. Upgrade and Delete an RPM
• To upgrade the package, if the package isn’t already installed:
• # rpm -Uvh nano-2.2.6-1.x86_64.rpm
• To delete an installed package, use the -e option to remove it:
• # rpm -e nano
• You can always reinstall the package at a later date if you keep the .rpm
file on your system (or you can always download it again).
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12. Querying and Verifying Packages
• Query the installed system packages
• # rpm -qa | grep [package name]
• Query the installed system packages for nano:
• # rpm -qa | grep nano
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13. man pages
• There is usually a documentation for a given package. This documentation is
known as a package’s man pages, and most packages come with them.
• To access the man pages, use the man command:
• # man nano
• Scroll up and down to view the documentation and press q to quit.
• man pages provide in-depth details, usage, and examples for any given
package.
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14. YUM (Yellow dog Update Modifier)
• The yum command has access to repositories where tons of
packages are kept and can install, upgrade, or remove them for you
automatically.
• Yum also takes care of resolving and installing any dependencies for
you, which the rpm command can’t do
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15. Syntax: yum [options] command
•Options:
• -c Specifies the location of the config file
• -q Specifies quiet, no output
• -y Indicates to always answer yes to prompts
• -v Provides verbose output
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16. Commands
• clean Removes cached data
• erase Removes a package from the system
• grouplist Displays available package groups
• groupinstall Installs the packages within a group
• Info Displays information about a package
• install Installs a package on the system
• search Enables you to search for a package
• update Updates a package
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17. Installing and Removing Packages
• Directly from the Red Hat repositories:
• # yum install -y postfix
• You could also update the postfix package. Just change the
command from install to update:
• # yum update -y postfix
• Use remove here because you don’t want anything lingering
around at the moment:
• # yum remove -y postfix
• One great feature about yum is that instead of updating a single
package, you can list all updates that need to be installed for the
system:
• # yum list updates
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18. YUM Commands
• From this list, you can choose to update packages individually or as
a whole. If you want to install all the updates, you can use the
following:
• # yum update
• Keeps a list of “groups” that contain a set of packages, making it
easier to install sets of packages together.
• The most common example would be if you wanted to install an X
server package so that your system has a GUI. You can use the
grouplist command to get a listing of all available “groups”:
• # yum grouplist
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19. Searching for Packages
• Gives you access to the repositories from which you can install
software
• Use the search command to query software packages from the
repositories.
• Find the postfix package to install:
• # yum search postfix
• To find out more information about the postfix package, use the
following command:
• # yum info postfix
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20. Clean Command
• One additional command that you can use with yum (rpm
doesn’t have an equivalent option) is the clean
command.
• It wipes the yum cache and forces it to sync with the Red
Hat repositories, giving you the most updated package
information.
• To flush the cache, do the following:
• # yum clean all
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21. Configuring Additional Repositories
• Sometimes you might want to install a package that isn’t in the
repositories that come preconfigured with Red Hat.
• If the package is available in someone else’s repository, you can
add that person’s repository to your yum config file.
• You can either add your own custom repositories to the main
config file /etc/yum.conf or create a .repo file in the
/etc/yum.repos.d directory, which will be added automatically.
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22. Configuring Additional Repositories
• Here is what a sample entry for a custom repository looks like:
[unique title]
name=My Custom Yum Repository
baseurl=ftp://rhel01/opt/yum/myrepos
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-
redhat-release
• This entry defines a name, a location, and whether or not the repository is
enabled.
• You can save this entry as a test.repo file in /etc/yum.repos.d, and you will
have access to any of the packages in the /opt/yum/myrepos repository on the
RHEL01 system.
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