other mail clients (such as mailx, elm). If the message can be appended to
the file, then this action succeeds.
.TP 4
-.I mmdf
-Identical to
-.IR file ,
-but always appends the message using the MMDF mailbox format.
-.TP 4
.IR pipe " or " |
Pipe the message as the standard input to the command named by
.IR string ,