Você deve adicionar o componente non-free
ao seu sources.list
edite seu sources.list
sudo apt edit-sources
da seguinte forma:
deb http://deb.debian.org/debian stretch main contrib non-free
deb-src http://deb.debian.org/debian stretch main contrib non-free
deb http://deb.debian.org/debian stretch-updates main contrib non-free
deb-src http://deb.debian.org/debian stretch-updates main contrib non-free
deb http://security.debian.org/ stretch/updates main contrib non-free
deb-src http://security.debian.org/ stretch/updates main contrib non-free
salve e execute:
sudo dpkg --add-architecture i386
sudo apt update
sudo apt install steamcmd
Verifique o pacote:
$ apt-cache search steamcmd
steamcmd - Command-line interface for Valve's Steam
$apt-cache policy steamcmd
steamcmd:i386:
Installé : (aucun)
Candidat : 0~20130205-1
Table de version :
0~20130205-1 500
500 http://deb.debian.org/debian stretch/non-free i386 Packages