YUM Package Manager

Yellowdog Updater Modified (yum) is a much easier package manager which works on rpm RPM-based system. The two attractive features of 'yum' when compared with 'rpm' is it resolves dependency automatically. It also can automatically perform the system update.

1. Overview

• YUM is also known as the Red Hat package manager.

• It provides the following functionalities:

  • Fetching information about available packages.

  • Installing and uninstalling packages.

  • Updating individual packages or the entire system to the latest versions.

  • Automatically resolving dependencies during package installation, removal, or updates.

2. Key Features

• Dependency Resolution: YUM ensures that all required dependencies are met when installing or updating packages.

• Repositories: YUM can be configured with additional repositories (sources of packages) beyond the default ones.

• Plug-ins: YUM supports various plug-ins to enhance its capabilities.

• Fast and Efficient: YUM performs tasks quickly, making it ideal for system administrators.

3. Common YUM Commands

Let's explore some common YUM commands:

a. Checking for Updates

You can verify available updates for installed packages using the following command:

yum check-update

This command lists package names, their versions, CPU architecture, and the repository where each package is available.

b. Installing and Updating Packages

• To install a package:

  yum install package-name

• To update a package:

  yum update package-name

c. Working with Transaction History

• Listing recent transactions:

  yum history list

• Examining a specific transaction:

  yum history info transaction-ID

• Reverting a transaction:

  yum history undo transaction-ID

d. Configuring YUM and Repositories

• Edit the main YUM configuration file:

  vi /etc/yum.conf

• Add or enable repositories:

  yum-config-manager --add-repo repository-URL

e. yum search <package-name>

• Searches for packages matching the specified name or keywords.

• Example:

  yum search htop

f. yum provides <file>

• Determines which package provides a specific file.

• Example:

  yum provides /usr/bin/htop

g. yum repolist

• Lists enabled repositories along with their status.

• Example:

  yum repolist

h. yum clean all

• Cleans temporary files and cached data.

• Removes metadata and improves system performance.

• Example:

  yum clean all

4. Lab Exercise

Let's create a simple lab exercise to practice using YUM:

1. Objective: Install the htop package.

2. Steps:

   • Check if htop is already installed:

     yum list installed htop

   • If not installed, install it:

     yum install htop

   • Verify the installation:

     htop