The following commands can be used while you are preparing a mail message in send mode.
To ... Do this
cancel the mail message ~x
preview the mail message ~p
add users to the Cc: list ~c users
add users to the Bcc: list ~b users
display this list of commands ~?
use the visual editor on your mail message ~v
insert a file into the mail message ~r filename
add your signature ~a or ~A
add users to the To: list ~t users
run a shell command ~! command
include output from a shell command ~<! command