Use pacman without breaking SteamOS
- Make sure your sudo password is set (use the
passwdcommand in Konsole if not) - Download the
.desktopfile above and open it in your file manager to start the install
Once installed, you can use the steamos-rw command to enable, disable, or reset your writeable overlay.
The overlay data is stored in a disk image at /home/.steamos/offload/usr.img alongside the rest of the SteamOS offload folders.
That disk image is mounted to /var/lob/overlays/usr alongside the etc overlay folder (var-lib-overlay-usr.mount).
Finally, overlayfs is used the same way as SteamOS does with the etc overlay to enable writing to the usr folder (usr.mount), which allows you to use pacman.
Additionally, all the pre-installed packages are added to the pacman IgnorePkg list (/etc/pacman.conf) to prevent you from borking your system with a pacman -Syu.
Next, the default mirrorlist (/etc/pacman.d/mirrorlist) has to have SigLevel = Optional TrustAll added to work at all, thanks to valve somehow breaking package/repo signing.
After initializing the pacman keyring, pacman-contrib is installed to get the paccache service, which will help prevent pacman cache from filling up the small /var partition.
To get systemd services like tailscale working, a system and user service (overlay-units.service) is added to issue start commands to enabled services, since they show up in the system too late for systemd to automatically start them.
Finally, steamos-rw.target and the steamos-rw command allow you to easily control the overlay.
You can also use steamos-rw reset to re-format the overlay disk image if you'd like to reset your installed software.