Arch Linux package manager pacman

A Practical Guide to Pacman & Yay

This guide provides a practical overview of pacman, the default package manager for Arch Linux, and yay, a popular AUR (Arch User Repository) helper.

pacman: The Arch Linux Package Manager

pacman is a powerful command-line utility that is one of the major distinguishing features of Arch Linux. It handles installing, upgrading, querying, and removing packages from the official repositories.

Core Operations

Package management can be thought of in a lifecycle: finding, installing, querying, and removing.

1. Synchronizing and Installing (-S)

These commands download packages from remote repositories.

• pacman -S <package>: Installs a specific package.
• pacman -Ss <search_term>: Searches the repositories for a package.
• pacman -Si <package>: Displays detailed information about a remote package.
• pacman -Syu: The most important command. Synchronizes the local package database (y) and then upgrades all out-of-date packages (u). This is the standard command to keep your system fully updated.
• pacman -Sc: Cleans the package cache. Use pacman -Scc to clear all cached files.

2. Querying Installed Packages (-Q)

These commands look at packages already installed on your local system. This is where the local/ repository name comes from, as seen in pacman -Qs. It means the package is on your local machine.

• pacman -Q: Lists all packages installed on your system.
• pacman -Qe: Lists only explicitly installed packages (not dependencies).
• pacman -Qd: Lists “orphans” (packages installed as a dependency that are no longer required).
• pacman -Qs <search_term>: Searches for an already-installed package.
• pacman -Qi <package>: Displays detailed information about an installed package.
• pacman -Ql <package>: Lists all files owned by a specific package.
• pacman -Qo <file_path>: Shows which package owns a specific file.

3. Removing Packages (-R)

These commands uninstall packages from your system.

• pacman -R <package>: Removes a package.
• pacman -Rs <package>: Recommended. Removes the target package and its dependencies that aren’t required by any other package.
• pacman -Rns <package>: A thorough removal command. It removes the package (R), its unneeded dependencies (s), and discards any backup configuration files(.pacsave) (n).

WARNING: Use the -c flag with extreme caution. The command pacman -Rcns <package> is very powerful and can be destructive. The c flag stands for cascade, and it removes the target package and everything else on the system that depends on it. This can easily lead to removing critical parts of your system by accident. For most use cases, pacman -Rns is the safer choice.

4. Installing from a Local File (-U)

• pacman -U <path/to/package.pkg.tar.zst>: Installs a package from a local file, such as one built from the AUR.

pactree: Visualizing Dependencies

pactree is a utility (included in pacman-contrib) that provides a clear tree view of dependencies.

• pactree <package>: Shows the forward dependency tree. It displays the package and everything it needs to function.
• pactree -r <package>: Shows the reverse dependency tree. It displays the package and everything that depends on it. This is perfect for figuring out why a certain package was installed.

yay: An AUR Helper

What is the AUR?

The Arch User Repository (AUR) is a vast, community-driven repository for Arch users. It contains package build scripts (PKGBUILDs) that allow you to compile and install software not available in the official repositories.

What is yay?

Since pacman cannot interact with the AUR directly, you need an AUR helper. yay is one of the most popular helpers. It acts as a wrapper around pacman, seamlessly integrating AUR packages with packages from the official repositories.

Common yay Commands

yay uses pacman’s syntax for most operations, making it very intuitive.

• yay: With no arguments, this is the equivalent of pacman -Syu but it also checks for and installs updates for AUR packages. This is the all-in-one command to keep your entire system updated.
• yay <package>: Searches for and installs a package from both the official repositories and the AUR.
• yay -Rns <package>: Uninstalls a package, using the same syntax as pacman.
• yay -Sua: Upgrades only AUR packages.
• yay -Ps: Prints system statistics, like uptime and package versions.
• yay -Yc: Cleans unneeded dependencies (orphans) from both official and AUR packages.

Reference

[1] https://wiki.archlinux.org/title/Pacman