Managing DNF Repositories

What is a Repository and How Do I See Them?

A repository, or "repo" for short, is a remote server that stores software packages and metadata about those packages. dnf uses this metadata to find packages and resolve dependencies. The configurations for these repositories are stored as simple text files ending in .repo in the /etc/yum.repos.d/ directory on your system.

The most direct way to see which repositories dnf is actively using is with the dnf repolist command.

dnf repolist

This command shows you the repositories that are currently enabled. For a more complete picture, including repositories that are configured but disabled, you can use the all argument.

dnf repolist all

Let's see a demonstration of this.

The output of dnf repolist typically includes three columns:

1. Repo ID: A short, unique identifier for the repository (e.g., fedora).
2. Repo Name: A longer, human-readable name (e.g., Fedora 40 - x86_64).
3. Status: The number of packages in the repo, or "disabled" if it's not active.

You can also specifically list only enabled or disabled repositories:

# List only enabled repositories (same as the default)
dnf repolist enabled




# List only disabled repositories
dnf repolist disabled

Enabling and Disabling Repositories

Why would you want to disable a repository? Sometimes a repository might contain unstable "testing" software, or you might want to prevent software from a specific source from being installed for security or policy reasons. Conversely, you might enable a repository to get access to specific software it contains.

There are two ways to do this: permanently and temporarily.

Permanent Changes with dnf config-manager

The recommended way to permanently enable or disable a repository is with the dnf config-manager command, which is part of the dnf-plugins-core package (it should be installed by default on your system). This tool directly and safely modifies the .repo configuration files for you.

To disable a repository, use its Repo ID:

sudo dnf config-manager --set-disabled <repo_id>

To enable it again:

sudo dnf config-manager --set-enabled <repo_id>

Temporary Changes for a Single Command

Sometimes, you only want to use a disabled repository for a single operation without enabling it permanently. For example, you might want to install one specific tool from a testing repo. You can do this with command-line flags.

• --enablerepo=<repo_id>: Enables a disabled repository for this one command.
• --disablerepo=<repo_id>: Disables an enabled repository for this one command.

For example, to install package-xyz from a disabled repo named updates-testing, you would run:

sudo dnf --enablerepo=updates-testing install package-xyz

This is a powerful technique for precise control over your package installations.

The following guide provides a clear walkthrough of all the commands we've just discussed.

For a quick, scannable reference of these commands, the "Repository Management" section of this cheat sheet is also very useful.

Your Turn: Hands-on Practice

Time to put this knowledge to use on your Fedora system. Open your terminal and work through these exercises.

• Exercise 1: List Your Active Repositories
  Run the command to list all currently enabled repositories on your system. Take a look at the IDs and names. Do they make sense? You should see fedora, updates, and likely fedora-cisco-openh264.

  Solution

  dnf repolist
  

• Exercise 2: Find a Disabled Repository
  Now, list all repositories, including disabled ones. Find the Repo ID of one that is disabled. A common one is updates-testing.

  Solution

  dnf repolist all
  
  
  
  # Look for a repository with the status 'disabled' in the output.
  

• Exercise 3: Disable a Repository
  The fedora-cisco-openh264 repository provides a video codec. It's a safe repository to practice with. Use dnf config-manager to disable it. After running the command, verify your change by listing the enabled repositories again. It should no longer appear in the list.

  Solution

  
  
  
  # 1. Disable the repository
  sudo dnf config-manager --set-disabled fedora-cisco-openh264
  
  
  
  
  # 2. Verify it is gone from the enabled list
  dnf repolist
  

• Exercise 4: Enable the Repository
  Now, reverse what you just did. Enable the fedora-cisco-openh264 repository again and verify that it has returned to the active list.

  Solution

  
  
  
  # 1. Enable the repository
  sudo dnf config-manager --set-enabled fedora-cisco-openh264
  
  
  
  
  # 2. Verify it is back in the enabled list
  dnf repolist
  

• Exercise 5: A Practical Search
  Let's simulate using a disabled repository for a single command. The updates-testing repository contains packages that are being tested before they are moved to the main updates repository. Let's search for the kernel package only in this repository without enabling it permanently.

  Solution

  
  
  
  # This command disables all repos ('*') and then enables only 'updates-testing' for this one search
  dnf --disablerepo="*" --enablerepo="updates-testing" search kernel
  

  This will show you any kernel related packages currently in the testing repository. This demonstrates how you can precisely target repositories for specific tasks.

Conclusion

Excellent work. You can now inspect and control the software sources your system uses. This is a foundational skill that moves you from being just a user to being a system administrator.

Key Takeaways:

• Repositories are the sources for all software installed via dnf. Their configuration lives in /etc/yum.repos.d/.
• dnf repolist shows your active software sources. Use dnf repolist all to see everything configured.
• You can permanently enable or disable repos using sudo dnf config-manager --set-enabled/--set-disabled.
• You can temporarily use a repo for a single command with the --enablerepo flag.

So far, you've worked with the repositories that came with your Fedora installation. But what happens when the program you need—especially for web development—isn't in any of them? In our next lesson, we will tackle exactly that by learning how to add a third-party DNF repository (RPM Fusion), which will vastly expand the software available to you.