Debian versions

squeeze(6), wheezy (7), jessie (8)

apt-get update;
apt-get -y install lsb-release; 
cat > /etc/apt/sources.list <<EOF
#archive
deb http://archive.debian.org/debian/ `lsb_release -cs` main non-free contrib
deb-src http://archive.debian.org/debian/ `lsb_release -cs` main non-free contrib
EOF

#remove previous sources
rm /etc/apt/sources.list.d/*
apt-get update; 

stretch (9), buster (10)

apt-get update;
apt-get -y install lsb-release; 
cat > /etc/apt/sources.list <<EOF
#archive
deb http://ftp.debian.org/debian/ `lsb_release -cs` main non-free contrib
deb-src http://ftp.debian.org/debian/ `lsb_release -cs` main non-free contrib
EOF

#remove previous sources
rm /etc/apt/sources.list.d/*
apt-get update;