trim - Trim mailbox headers
Trim reads through your mailbox file and copies its contents into a file in your home directory called “mail.t” (if it already exists, trim appends new letters to it). While copying your mailbox, trim removes all header fields except for the following which start with:
From Date: From: Subject: To: Cc: Bcc:
This significantly reduces the size of Internet-originated messages which contain a number of header lines. When trim has finished pruning your mailbox, it asks if you want it deleted. Normally, you would want it removed, as your mail has been copied into “mail.t” in your directory.
To work with “mail.t” file as your mailbox, invoke the mailer as follows:
mail -m mail.t