Here is a script I used on a Linux server to always keep PFCMARK 10
years ahead.
cat /usr/local/bin/SET_PFCMARK
YEAR=`date '+%G'`;
YEAR=$((YEAR + 10));
PFCMARK="${YEAR:2:2}";
export PFCMARK
I set it in /etc/profile.d/filepro.sh and in my rc.local file.
I used this syntax . /usr/local/bin/SET_PFCMARK.
Richard D. Williams