Print a "To:" line at the heading of the letter, showing the names of the recipients.
Force mail to be sent to remote users without waiting for remote transfer program to be completed.
Store message in a file named after the first recipient.
Stop trying to send after making
n network connections, or "hops"
(useful for avoiding infinite loops).
Ignore interrupts (useful on modems).
Specify a return
address for mail you send.
subject in the subject header field.
Convert uucp-type addresses to Internet format.
Verbose; display status of mail delivery.
Test for the existence of mail without printing it. Exit status is 0 if mail exists; otherwise 1.
Read mail from alternate mailbox
Forward all incoming mail to recipient
Display a window of messages rather than the latest message.
Print all messages without pausing.
Print messages with all header lines displayed.
Terminate on an interrupt.
Print oldest messages first.