V8/usr/src/cmd/Mail/manual/cmds/if

.ip \fBif\fP
Commands in your
.q .mailrc
file can be executed conditionally depending on whether you are
sending or receiving mail with the
.b if
command.  For example, you can do:
.(l
if receive
	\fIcommands\fP...
endif
.)l
An
.b else
form is also available:
.(l
if send
	\fIcommands\fP...
else
	\fIcommands\fP...
endif
.)l
Note that the only allowed conditions are
.b receive
and
.b send .