How to enable multilib on Arch Linux

Even with all of the packages available in the Arch User Repository (AUR) it
wouldn’t be Arch if I didn’t run into a scenario where I needed to install something from another repository other than the ones that I had enabled out of the box.

The package in question would be the Steam client.

Even though I do the majority of my Steam gaming on the Steam Deck, there are a handful of games that I prefer to play on the computer.

I believe the reason that Steam requires the additional multilib repository to
be enabled is due to it needing to use 32-bit libraries, which aren’t available
by default on Arch Linux.

Not a big deal though, all you need to do is edit the /etc/pacman.conf file
with your favorite text editor, remove the comments from a few lines, and then
update.

First, open the file (as a super user):

% vim /etc/pacman.conf

Then look for the line [multilib], for me, it was on line 90, but YMMV. Remove the comments from that line, and the line below it, so it goes from this:

#[multilib]
#Include = /etc/pacman.d/mirrorlist

To this:

[multilib]
Include = /etc/pacman.d/mirrorlist

Save the file and exit your text editor, and then you can run pacman to get
things all updated with the new repository:

% pacman -Syyu

Then you are ready to be able to install packages from the multilib universe:

% pacman -S steam