GNU Mailutils Manual (split by node):   Section:   Chapter:FastBack: Programs   Up: Composing Mail   FastForward: Libraries   Contents: Table of ContentsIndex: Function Index Printing And Saving the Message

The ‘~p’ escape types the contents of the message entered so far, including headers, on your terminal. You can save the message to an arbitrary file using ‘~w’ escape. It takes the filename as its argument.