Populate /root/sups with supfiles copied from /usr/share/examples/cvsup
mkdir -p /root/sups cp /usr/share/examples/cvsup/ports-supfile /root/sups/ports.sup cp /usr/share/examples/cvsup/stable-supfile /root/sups/RELENG_8_0.sup
Patch the supfiles to indicate your server du jour
suptag="RELENG_8_0" supsrv="cvsup14.FreeBSD.org" sed -e "s/^\(\*default host=\).*$/\1${supsrv}/g" -e "s/^\(\*default release=cvs tag=\).*$/\1${suptag}/g" -i /root/sups/RELENG_8_0.sup sed -e "s/^\(\*default host=\).*$/\1${supsrv}/g" -i /root/sups/ports.sup
Patch make.conf to indicate your desire to use sup update
cat <<EOF >> /etc/make.conf # SUP Update SUP_UPDATE=yes SUP=/usr/bin/csup SUPFILE=/root/sups/RELENG_8_0.sup PORTSSUPFILE=/root/sups/ports.sup EOF
Now you can issue a simple 'make update' from within /usr/src or /usr/ports to automatically refresh the sources via cvsup