SteamOS is a Linux distribution developed by Valve. It incorporates Valve's popular namesake Steam video game storefront and is the primary operating system for Steam Machines and the Steam Deck. SteamOS is open source with some closed source components.
SteamOS was originally built to support streaming of video games from one personal computer to the one running SteamOS within the same network, although the operating system can support standalone systems and was intended to be used as part of Valve's Steam Machine platform. SteamOS versions 1.0, released in December 2013, and 2.0 were based on the Debian distribution of Linux with GNOME desktop. With SteamOS, Valve encouraged developers to incorporate Linux compatibility into their releases to better support Linux gaming options.
In February 2022, Valve released the handheld gaming computer Steam Deck running SteamOS 3.0. SteamOS 3 is based on the Arch Linux distribution with KDE Plasma 5.
Arch chroot install
This is for installing and using programs like 'tmux' and 'neofetch' on the Steam Deck and it be kept after an OS upgrade. This will set up and install a chroot environment so there is a file system structure in which pacman can download and install packages and their dependencies within here. A chroot environment is not necessary but it can be added it to the $PATH.
mkdir -p ~/.local/chroot cd ~/.local sudo mv /etc/pacman.d/mirrorlist /etc/pacman.d/mirrorlist.BAK sudo touch /etc/pacman.d/mirrorlist sudo chmod 777 /etc/pacman.d/mirrorlist sudo echo "Server = https://geo.mirror.pkgbuild.com/\$repo/os/\$arch" >> /etc/pacman.d/mirrorlist sudo chmod 644 /etc/pacman.d/mirrorlist sudo pacman -Sy archlinux-keyring sudo pacman-key --populate archlinux sudo pacman-key --refresh-keys sudo pacstrap ./chroot base base-devel archlinux-keyring nano htop echo alias pac=\'sudo pacstrap -C /home/deck/.local/chroot/etc/pacman.conf /home/deck/.local/chroot\' >> ~/.bashrc touch /etc/ld.so.conf.d/deck-local-arch.conf echo export PATH=\"$PATH:/home/deck/.local/chroot/bin/\" >> ~/.bashrc sudo mv /etc/pacman.d/mirrorlist /etc/pacman.d/mirrorlist.BAK2 ; sudo mv /etc/pacman.d/mirrorlist.BAK /etc/pacman.d/mirrorlist
Now those packages are accessible for use as the 'deck' user from within SteamOS. It does not work for every package like those requiring a kernel module or systemd service but most normal shell tools will work. Install using 'pac package'.