Converting Mbox mailboxes to Maildir format

Overview

Maildir is a structure for directories of incoming mail messages that solves the reliability problems that plague mbox files. A directory in maildir format has three subdirectories, all on the same filesystem: tmp, new, and cur.

Each file in new is a newly delivered mail message. Files in cur are just like files in new. The big difference is that files in cur are no longer new mail: they have been seen by the user's mail-reading program. The tmp directory is used to ensure reliable delivery. For a new user who does not have existing mail messages in mbox format, all that is required is to create the ~/Maildir directory and its tmp, new, and cur subdirectories all owned by the user.