Find all *.htm files under current directory and print the changed names by appending 3 levels of parent directory names at the beginning and modifying the actual name to dd-nnn format
find -type f -name "*.htm" | awk -F'[/]' 'BEGIN{OFS="-"}{ gsub(/^\.\//,"") ;print $1,$2, substr($4,3,2),substr($4,5,2),substr($4,8) }'