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

.ip \fBheaders\fP
When you start up
.i Mail
to read your mail, it lists the message headers that you have.
These headers tell you who each message is from, when they were
sent, how many lines and characters each message is, and the
.q "Subject:"
header field of each message, if present.  In addition,
.i Mail
tags the message header of each message that has been the object
of the
.b preserve
command with a
.q P.
Messages that have been
.b saved
or
.b written
are flagged with a
.q *.
Finally,
.b deleted
messages are not printed at all.  If you wish to reprint the current
list of message headers, you can do so with the
.b headers
command.  The
.b headers
command (and thus the initial header listing)
only lists the first so many message headers.
The number of headers listed depends on the speed of your
terminal.
This can be overridden by specifying the number of headers you
want with the
.i window
option.
.i Mail
maintains a notion of the current
.q window
into your messages for the purposes of printing headers.
Use the
.b z
command to move forward and back a window.
You can move
.i Mail's
notion of the current window directly to a particular message by
using, for example,
.(l
headers 40
.)l
to move
.i Mail's
attention to the messages around message 40.  The
.b headers
command can be abbreviated to
.b h .