These scripts are written for steamcmd servers

step 1 : install steamcmd
create user steamcmd
# useradd -m -b/path/to/user -s /bin/bash steamcmd

su to your steamcmd user
# su - steamcmd

add non-free repositories to your aptitude /etc/apt/sources.list (not sure securityi non-free has any use here)
# deb http://ftp.fr.debian.org/debian/ stretch main contrib non-free
# deb-src http://ftp.fr.debian.org/debian/ stretch main contrib non-free
# deb http://security.debian.org/debian-security stretch/updates main contrib non-free
# deb-src http://security.debian.org/debian-security stretch/updates main contrib non-free
# deb http://ftp.fr.debian.org/debian/ stretch-updates main contrib non-free
# deb-src http://ftp.fr.debian.org/debian/ stretch-updates main contrib non-free

allow steamcmd user to install steamcmd on your system in your sudoers /etc/sudoers
# steamcmd ALL=(ALL) NOPASSWD: /usr/bin/apt-get install steamcmd

deploy steamcmd
# steamcmd@yourSystem:$ sudo /usr/bin/apt-get install steamcmd

run steamcmd to update it
# steamcmd@yourSystem:$ steamcmd

step 2 : get the scripts from git into the homedir of your steamcmd user ~steamcmd/scripts_jeux