/dir/ means exclude the root folder /dir
/dir/* means get the root folder /dir but not the contents
dir/ means exclude any folder anywhere where the name contains dir/
Examples excluded: /dir/, /usr/share/mydir/, /var/spool/dir/
/dir means exclude any folder anywhere where the name contains /dir
Examples excluded: /dir/, /usr/share/directory/, /var/spool/dir/
/var/spool/lpd//cf means skip files that start with cf within any folder
within /var/spool/lpd