Obviously, the answer to the question in the title is yes. But I really want to know if I can do it without breaking anything.
I am using offlineimap to back up my Gmail account to a Maildir on my local computer. Since Gmail lets you easily assign multiple labels to your mail, my backup directory ends up with multiple copies of most of my mails. I would like to save space by replacing copies of the same message with hard links, using a script called hardlink. Could this possibly cause problems for applications using the Maildir, or could it cause applications to corrupt my mailboxes? Or would modification of any mail files simply break any hard links associated with that file, without affecting the previous version that was hard-linked elsewhere?