mail.1

.\"	$OpenBSD: mail.1,v 1.5 1994/06/29 05:09:32 deraadt Exp $
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.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
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.\"	from: @(#)mail.1	8.2 (Berkeley) 12/30/93
.\"
.Dd December 30, 1993
.Dt MAIL 1
.Os BSD 4
.Sh NAME
.Nm mail
.Nd send and receive mail
.Sh SYNOPSIS
.Nm mail
.Op Fl iInv
.Op Fl S Ar var[=value]
.Op Fl s Ar subject
.Op Fl c Ar cc-addr
.Op Fl b Ar bcc-addr
.Ar to-addr...
.Nm mail
.Op Fl iInNv
.Op Fl S Ar var[=value]
.Op Fl e Ar command
.Fl f
.Op Ar name
.Nm mail
.Op Fl iInNv
.Op Fl S Ar var[=value]
.Op Fl e Ar command
.Op Fl F Ar boxvar
.Nm mail
.Op Fl iInNv
.Op Fl S Ar var[=value]
.Op Fl e Ar command
.Op Fl u Ar user
.Sh INTRODUCTION
.Nm Mail
is an intelligent mail processing system, which has
a command syntax reminiscent of
.Xr \&ed 1
with lines replaced by messages.
.Pp
.Bl -tag -width flag
.It Fl v
Verbose mode.
The details of
delivery are displayed on the user's terminal.
.It Fl i
Ignore tty interrupt signals.
This is
particularly useful when using
.Nm mail
on noisy phone lines.
.It Fl I
Forces mail to run in interactive mode even when
input isn't a terminal.
In particular, the
.Sq Ic \&~
special
character when sending mail is only active in interactive mode.
.It Fl n
Inhibits reading
.Pa /etc/mail.rc
upon startup.
.It Fl N
Inhibits the initial display of message headers
when reading mail or editing a mail folder.
.It Fl S
Acts as if a
.Ar set
for
.Ar var[=value]
had been seen in a start-up RC file, except that backticks are not
executed. Can be used more than once.
.It Fl s
Specify subject on command line
(only the first argument after the
.Fl s
flag is used as a subject; be careful to quote subjects
containing spaces.)
.It Fl c
Send carbon copies to
.Ar list
of users.
.It Fl b
Send blind carbon copies to
.Ar list .
List should be a comma-separated list of names.
.It Fl e
When reading mail, execute the
.Ar command
as if it were the first interactive input. (Can only be used once.)
.It Fl f
Read in the contents of your
.Ar mbox
(or the specified file)
for processing; when you
.Ar quit  ,
.Nm mail
writes undeleted messages back to this file.
.It Fl F
Takes a
.Ar boxvar
argument and then works like 
.Dl mail -f /some/path/file
would if your
.Pa \&.mailrc
file contained the line
.Dl set boxvar=/some/path/file
.It Fl u
Is equivalent to:
.Dl mail -f /var/spool/mail/user
(but is overridden if the environment variable
.Em MAIL
is set).
.El
.Ss Sending mail
To send a message to one or more people,
.Nm mail
can be invoked with arguments which are the names of people to
whom the mail will be sent.
You are then expected to type in
your message, followed
by an
.Sq Li control\-D
at the beginning of a line.
The section below
.Ar Replying to or originating mail ,
describes some features of
.Nm mail
available to help you compose your letter.
.Pp
.Ss Reading mail
In normal usage
.Nm mail
is given no arguments and checks your mail out of the
post office, then
prints out a one line header of each message found.
The current message is initially the first message (numbered 1)
and can be printed using the
.Ic print
command (which can be abbreviated
.Ql Ic p ) .
You can move among the messages much as you move between lines in
.Xr \&ed 1 ,
with the commands
.Ql Ic \&+
and
.Ql Ic \&\-
moving backwards and forwards, and
simple numbers.
.Pp
.Ss Disposing of mail.
After examining a message you can
.Ic delete 
.Pq Ic d
the message or
.Ic reply
.Pq Ic r
to it.
Deletion causes the
.Nm mail
program to forget about the message.
This is not irreversible; the message can be
.Ic undeleted
.Pq Ic und
by giving its number, or the
.Nm mail
session can be aborted by giving the
.Ic exit
.Pq Ic x
command.
Deleted messages will, however, usually disappear never to be seen again.
.Pp
.Ss Specifying messages
Commands such as
.Ic print ,
.Ic from ,
and
.Ic delete
can be given a list of message numbers as arguments to apply
to a number of messages at once.
Thus
.Dl delete 1 2
deletes messages 1 and 2, while
.Dl delete 1\-5
deletes messages 1 through 5.
Similarly search terms can be used. Show a one line summary of messages
from john:
.Dl from john
Or find messages with IMPORTANT in the subject:
.Dl from /IMPORTANT
(use quotes starting before the 
.Ql Li \&/
if the search string has spaces).
.Pp
Messages can also be searched for by size, for finding space hogs.
The general format is 
.Ic OPERATOR SIZE [ FLAG ]
where OPERATOR is one of 
.Ql Li \&<
,
.Ql Li \&>
, or
.Ql Li \&=
, SIZE is a number, and FLAG determines if measuring lines or bytes, or
batches of those. The FLAG can be:
.Bl -tag -width flag
.It Ic l
lines in a message (the default if no FLAG is given, but needed if another
filter follows)
.It Ic C
hundreds of lines in a message
.It Ic b
bytes in a message
.It Ic K
kilobytes (1024 bytes) in a message
.It Ic M
megabytes in a message
.El
.Pp
There is also a 
.Ql Li \&#
operator with similar syntax intended to select the message at a particular
line or byte offset into the entire file. (The other flags can still be used,
eg
.Ql Li C
means the number given should be multiplied by 100 and then used as a line
number, if you ever might want to do that.) Selecting a message by line
offset is default and particularly useful in conjunction with tools like
.Xr grep 1
which can report a line number of something interesting.
.Pp
Message searches can be filtered by various attributes like "new" or "old"
using the colon operator:
.Bl -tag -width flag
.It Ic :d
messages marked for deletion (otherwise hidden)
.It Ic :f
user flagged messages (saved between sessions)
.It Ic :m
user marked messages (not saved between sessions)
.It Ic :n
new messages
.It Ic :o
old messages (either from a previous session or read this session)
.It Ic :u
unread messages (either from a previous session or new)
.It Ic :B
messages with both a mark and a flag
.It Ic :U
messages with neither a mark nor a flag
.El
.Pp
Consider the sequence of commands:
.Pp
.Dl mark jane
.Dl flag /photos
.Dl from \&>1M :B
.Pp
This will mark the messages from "jane", then flag the messages with "Photos"
in the subject, and finally print the one line summary for messages over a
megabyte that are both flagged and marked.
.Pp
The special name
.Ql Li \&*
addresses all messages,
.Ql Li \&!
reuses the previous specified set,
.Ql Li \&~
uses the inverse of the previous specified set,
.Ql Li \&^
names the first message, and
.Ql Li \&$
addresses
the last message; thus the command
.Ic top
which prints the first few lines of a message could be used in
.Dl top \&!
to print the first few lines of all messages of the previous
.Dl from '%to:mail list'
search.
.Pp
.Ss Replying to or originating mail.
You can use the
.Ic rnmail
command to invoke an external mailer to reply to a message. The mailer
is defined by variable
.Em RNMAIL
and is assumed to work like the 
.Xr Rnmail
program included with the
.Xr trn
newsreader.
You mail also use the
.Ic reply
command to
compose a response to a message using the internal mailer,
sending it back to the person who it was from.
Text you then type in, up to an end-of-file,
defines the contents of the message.
While you are composing a message,
.Nm mail
treats lines beginning with the character
.Ql Ic \&~
specially.
For instance, typing
.Ql Ic \&~m
(alone on a line) will place a copy
of the current message into the response right shifting it by a tabstop
(see
.Em indentprefix
variable, below).
Other escapes will set up subject fields, add and delete recipients
to the message and allow you to escape to an editor to revise the
message or to a shell to run some commands.
(These options
are given in the summary below.)
.Pp
.Ss Ending a mail processing session.
You can end a
.Nm mail
session with the
.Ic quit
.Pq Ic q 
command.
Messages which have been examined go to your
.Ar mbox
file unless they have been deleted in which case they are discarded.
Unexamined messages go back to the post office.
(See the
.Fl f
option above).
.Pp
.Ss Personal and systemwide distribution lists.
It is also possible to create a personal distribution lists so that,
for instance, you can send mail to
.Dq Li cohorts
and have it go
to a group of people. Note that these do not work with
the external mailer program.
Such lists can be defined by placing a line like
.Pp
.Dl alias cohorts bill ozalp jkf mark kridle@ucbcory
.Pp
in the file
.Pa \&.mailrc
in your home directory.
The current list of such aliases can be displayed with the
.Ic alias
command in
.Nm mail  .
System wide distribution lists can be created by editing
.Pa /etc/aliases ,
see
.Xr aliases  5
and
.Xr sendmail  8  ;
these are kept in a different syntax.
In mail you send, personal aliases will be expanded in mail sent
to others so that they will be able to
.Ic reply
to the recipients.
System wide
.Ic aliases
are not expanded when the mail is sent,
but any reply returned to the machine will have the system wide
alias expanded as all mail goes through
.Xr sendmail  .
.Pp
.Ss Network mail (ARPA, UUCP, Berknet)
See
.Xr mailaddr 7
for a description of network addresses.
.Pp
.Nm Mail
has a number of options which can be set in the
.Pa .mailrc
file to alter its behavior; thus
.Dq Li set askcc
enables the
.Ar askcc
feature.
(These options are summarized below.)
.Sh SUMMARY
(Adapted from the `Mail Reference Manual')
.Pp
Each command is typed on a line by itself, and may take arguments
following the command word.
The command need not be typed in its
entirety \- the first command which matches the typed prefix is used.
For commands which take message lists as arguments, if no message
list is given, then the next message forward which satisfies the
command's requirements is used.
If there are no messages forward of
the current message, the search proceeds backwards, and if there are no
good messages at all,
.Nm mail
types
.Dq Li No applicable messages
and
aborts the command.
.Bl -tag -width delete
.It Ic \&\-
Print out the preceding message.
If given a numeric
argument
.Ar n  ,
goes to the
.Ar n Ns 'th
previous message and prints it.
.It Ic \&?
Prints a brief summary of commands from the default file or from
.Ar helpfile .
With a parameter, provides help on that subject.
.It Ic \&!
Executes the shell
(see
.Xr sh 1
and
.Xr csh 1 )
command which follows.
.It Ic Print
.Pq Ic P
Like
.Ic print
but also prints out ignored header fields.
See also
.Ic print ,
.Ic ignore
and
.Ic retain .
.It Ic Reply
.Pq Ic R
Reply to originator.
Does not reply to other
recipients of the original message.
.It Ic Rnmail
.Pq Ic Rn
replies to a message using an external mailer set in the
.Em RNMAIL
variable. The mailer will be invoked with a filename containing
the message to be replied to and is expected to send mail itself.
.It Ic alias
.Pq Ic a
With no arguments, prints out all currently-defined aliases.
With one
argument, prints out that alias.
With more than one argument, creates
a new alias or changes an old one.
.It Ic alternates
.Pq Ic alt
The
.Ic alternates
command is useful if you have accounts on several machines.
It can be used to inform
.Nm mail
that the listed addresses are really you.
When you
.Ic reply
to messages,
.Nm mail
will not send a copy of the message to any of the addresses
listed on the
.Ic alternates
list.
If the
.Ic alternates
command is given with no argument, the current set of alternate
names is displayed.
.It Ic chdir
.Pq Ic c
Changes the user's working directory to that specified, if given.
If
no directory is given, then changes to the user's login directory.
.It Ic copy
.Pq Ic co
The
.Ic copy
command does the same thing that
.Ic save
does, except that it does not mark the messages it
is used on for deletion when you quit.
.It Ic Copy
.Pq Ic C
Just like
.Ic copy
except a variable name holds the save file.
.It Ic delete
.Pq Ic d
Takes a list of messages as argument and marks them all as deleted.
Deleted messages will not be saved in
.Ar mbox  ,
nor will they be available for most other commands.
.It Ic dp
(also
.Ic dt )
Deletes the current message and prints the next message.
If there is no next message,
.Nm mail
says
.Dq Li "at EOF" .
.It Ic echo
.Pq Ic ec
Does variable and tilde expansion of arguments. Useful to show 
specific variable values.
.It Ic edit
.Pq Ic e
Takes a list of messages and points the text editor at each one in
turn.
On return from the editor, the message is read back in. See
.Ic visual
for a fullscreen version.
.It Ic exit
.Pf ( Ic ex
or
.Ic x )
Effects an immediate return to the Shell without
modifying the user's system mailbox, his
.Ar mbox
file, or his edit file in
.Fl f  .
.It Ic file
.Pq Ic fi
The same as
.Ic folder  .
.It Ic flag
.Pq Ic fl
Associates a flag with messages that can be used as a search filter and
will be saved with the message. See also
.Ic mark  .
.It Ic folders
List the names of the folders in your folder directory.
.It Ic folder
.Pq Ic fo
The
.Ic folder
command switches to a new mail file or folder.
With no
arguments, it tells you which file you are currently reading.
If you give it an argument, it will write out changes (such
as deletions) you have made in the current file and read in
the new file.
Some special conventions are recognized for
the name.
# means the previous file, % means your system
mailbox, %user means user's system mailbox, & means
your
.Ar mbox
file, and
\&+\&folder means a file in your folder
directory.
.It Ic Folder
This works just like
.Ic folder
except that a variable is used for the new file name.
.It Ic from
.Pq Ic f
Takes a list of messages and prints the one line message summary, in
the normal index format. Use with search patterns to find particular
message numbers.
.It Ic headers
.Pq Ic h
Lists the current range of headers, which is an 18\-message group.
If
a
.Ql \&+
argument is given, then the next 18\-message group is printed, and if
a
.Ql \&\-
argument is given, the previous 18\-message group is printed.
.It Ic help
A synonym for
.Ic \&?
.It Ic hold
.Pf ( Ic ho ,
also
.Ic preserve )
Takes a message list and marks each
message therein to be saved in the
user's system mailbox instead of in
.Ar mbox  .
Does not override the
.Ic delete
command.
.It Ic if...else...endif
Can be used only evaluate commands in certain contexts. Intended for 
use in 
.Dq Pa ~/.mailrc
there are four recognized conditions.
.Ar if reading
for reading mode;
.Ar if sending
when invoked to compose mail directly;
.Ar if etbmail
used to hide configuration from incompatable programs that might
also read
.Dq Pa ~/.mailrc ;
and lastly
.Ar if heirloom
used to hide configuration from this program by my version of
.Ic nail 
(project name "heirloom-mailx").
The last two forms are not recognized by older versions of
.Ic mail
or
.Ic nail
and will abort processing of the file.
.It Ic ignore
Add the list of header fields named to the
.Ar ignored list .
Header fields in the ignore list are not printed
on your terminal when you print a message.
This
command is very handy for suppression of certain machine-generated
header fields.
The
.Ic Print
command can be used to print a message in its entirety, including
ignored fields.
If
.Ic ignore
is executed with no arguments, it lists the current set of
ignored fields.
.It Ic interest
Add the list of header fields named to the
.Ar interesting list .
Header fields that are "interesting" are shown when using the
.Ic summary
command.
.It Ic highlight
Add the list of header fields named to the
.Ar highlighted list .
Header fields in the highlighted list are printed with
.Ar starthlstr
in front and 
.Ar endhlstr
after for the various type and print commands.
.It Ic list
Shows all available commands in search order. For an abbreviation
.Ar short ,
the first command in the list starting with "short"
is the one that will be used.
.It Ic mail
.Pq Ic m
Takes as argument login names and distribution group names and sends
mail to those people.
.It Ic mark
.Pq Ic mar
Associates a mark with messages that can be used as a search filter but
will not be saved. See also
.Ic flag  .
.It Ic mbox
Indicate that a list of messages be sent to
.Ic mbox
in your home directory when you quit.
This is the default
action for messages if you do
.Em not
have the
.Ic hold
option set.
.It Ic next
.Pq Ic n
like
.Ic \&+
or
.Tn CR )
Goes to the next message in sequence and types it.
With an argument list, types the next matching message.
.It Ic preserve
.Pq Ic pre
A synonym for
.Ic hold  .
.It Ic print
.Pq Ic p
Takes a message list and types out each message on the user's terminal.
.It Ic quit
.Pq Ic q
Terminates the session, saving all undeleted, unsaved messages in
the user's
.Ar mbox
file in his login directory, preserving all messages marked with
.Ic hold
or
.Ic preserve
or never referenced
in his system mailbox, and removing all other messages from his system
mailbox.
If new mail has arrived during the session, the message
.Dq Li "You have new mail"
is given.
If given while editing a
mailbox file with the
.Fl f
flag, then the edit file is rewritten.
A return to the Shell is
effected, unless the rewrite of edit file fails, in which case the user
can escape with the
.Ic exit
command.
.It Ic reply
.Pq Ic r
Takes a message list and sends mail to the sender and all
recipients of the specified message.
The default message must not be deleted.
.It Ic retain
Add the list of header fields named to the
.Ar retained list
Only the header fields in the retain list
are shown on your terminal when you print a message.
All other header fields are suppressed.
The
.Ic Type
and
.Ic Print
commands can be used to print a message in its entirety.
If
.Ic retain
is executed with no arguments, it lists the current set of
retained fields.
.It Ic rnmail
A synonym for
.Ic Rnmail  .
.It Ic save
.Pq Ic s
Takes a message list and a filename and appends each message in
turn to the end of the file.
The filename in quotes, followed by the line
count and character count is echoed on the user's terminal.
.It Ic Save
.Pq Ic S
Just like
.Ic save
except a variable name holds the save file.
.It Ic set
.Pq Ic se
With no arguments, prints all variable values.
Otherwise, sets
option.
Arguments are of the form
.Ar option=value
(no space before or after =) or
.Ar option .
Quotation marks may be placed around any part of the assignment statement to
quote blanks or tabs, i.e.
.Dq Li "set indentprefix=\*q->\*q"
Inside quotes, 
.Ic \&^x
can be used to include control characters. With
.Ic \&`
backtick quotes
.Ic \&`
the expression will be evaluated as a command.
.It Ic saveignore
.Ic Saveignore
is to
.Ic save
what
.Ic ignore
is to
.Ic print
and
.Ic type  .
Header fields thus marked are filtered out when
saving a message by
.Ic save
or when automatically saving to
.Ar mbox  .
.It Ic saveretain
.Ic Saveretain
is to
.Ic save
what
.Ic retain
is to
.Ic print
and
.Ic type  .
Header fields thus marked are the only ones saved
with a message when saving by
.Ic save
or when automatically saving to
.Ar mbox  .
.Ic Saveretain
overrides
.Ic saveignore  .
.It Ic shell
.Pq Ic sh
Invokes an interactive version of the shell.
.It Ic size
Takes a message list and prints out the size in characters of each
message.
.It Ic source
The
.Ic source
command reads
commands from a file.
.It Ic summary
Prints the
.Ic interesting
headers from messages. The headers default to "To", "From", "Subject",
and "CC" but an explicit list can be made with the
.Ic interest
command.
.It Ic top
Takes a message list and prints the top few lines of each.
The number of
lines printed is controlled by the variable
.Ic toplines
and defaults to five.
.It Ic touch
.Pq Ic tou
Consider the message(s) to be read.
.It Ic unalias
Takes a list of names defined by
.Ic alias
commands and discards the remembered groups of users.
The group names
no longer have any significance.
.It Ic undelete
.Pq Ic u
Takes a message list and marks each message as
.Ic not
being deleted.
.It Ic unflag
.Pq Ic unf
Removes the flag associated with a message.
.It Ic unmark
.Pq Ic unm
Removes the mark associated with a message.
.It Ic unread
.Pq Ic U
Takes a message list and marks each message as
.Ic not
having been read.
.It Ic unset
Takes a list of option names and discards their remembered values;
the inverse of
.Ic set  .
.It Ic visual
.Pq Ic v
Takes a message list and invokes the display editor on each message.
.It Ic write
.Pq Ic w
Similar to
.Ic save  ,
except that
.Ic only
the message body
.Pq Ar without
the header) is saved.
Extremely useful for such tasks as sending and receiving source
program text over the message system.
.It Ic Write
.Pq Ic W
Similar to
.Ic write  ,
except that a variable name holds the file to write.
.It Ic xit
.Pq Ic x
A synonym for
.Ic exit  .
.It Ic z
.Nm Mail
presents message headers in windowfuls as described under the
.Ic headers
command.
You can move
.Nm mail Ns 's
attention forward to the next window with the
.Ic \&z
command.
Also, you can move to the previous window by using
.Ic \&z\&\-  .
.El
.Ss Tilde/Escapes
.Pp
Here is a summary of the tilde escapes,
which are used when composing messages to perform
special functions.
Tilde escapes are only recognized at the beginning
of lines.
The name
.Dq Em tilde\ escape
is somewhat of a misnomer since the actual escape character can be set
by the option
.Ic escape .
.Bl -tag -width Ds
.It Ic \&~! Ns Ar command
Execute the indicated shell command, then return to the message.
.It Ic \&~b Ns Ar name ...
Add the given names to the list of carbon copy recipients but do not make
the names visible in the Cc: line ("blind" carbon copy).
.It Ic \&~c Ns Ar name ...
Add the given names to the list of carbon copy recipients.
.It Ic \&~d
Read the file
.Dq Pa dead.letter
from your home directory into the message.
.It Ic \&~e
Invoke the text editor on the message collected so far.
After the
editing session is finished, you may continue appending text to the
message.
.It Ic \&~f Ns Ar messages
Read the named messages into the message being sent.
If no messages are specified, read in the current message.
Message headers currently being ignored (by the
.Ic ignore
or
.Ic retain
command) are not included.
.It Ic \&~F Ns Ar messages
Identical to
.Ic \&~f ,
except all message headers are included.
.It Ic \&~h
Edit the message header fields by typing each one in turn and allowing
the user to append text to the end or modify the field by using the
current terminal erase and kill characters.
.It Ic \&~m Ns Ar messages
Read the named messages into the message being sent, indented by a
tab or by the value of
.Ar indentprefix  .
If no messages are specified,
read the current message.
Message headers currently being ignored (by the
.Ic ignore
or
.Ic retain
command) are not included.
.It Ic \&~M Ns Ar messages
Identical to
.Ic \&~m ,
except all message headers are included.
.It Ic \&~p
Print out the message collected so far, prefaced by the message header
fields.
.It Ic \&~q
Abort the message being sent, copying the message to
.Dq Pa dead.letter
in your home directory if
.Ic save
is set.
.It Ic \&~r Ns Ar filename
Read the named file into the message.
.It Ic \&~s Ns Ar string
Cause the named string to become the current subject field.
.It Ic \&~\&t Ns Ar name ...
Add the given names to the direct recipient list.
.It Ic \&~\&v
Invoke an alternate editor (defined by the
.Ev VISUAL
option) on the
message collected so far.
Usually, the alternate editor will be a
screen editor.
After you quit the editor, you may resume appending
text to the end of your message.
.It Ic \&~w Ns Ar filename
Write the message onto the named file.
.It Ic \&~\&| Ns Ar command
Pipe the message through the command as a filter.
If the command gives
no output or terminates abnormally, retain the original text of the
message.
The command
.Xr fmt 1
is often used as
.Ic command
to rejustify the message.
.It Ic \&~: Ns Ar mail-command
Execute the given mail command.
Not all commands, however, are allowed.
.It Ic \&~~ Ns Ar string
Insert the string of text in the message prefaced by a single ~.
If
you have changed the escape character, then you should double
that character in order to send it.
.El
.Ss Mail Options
Options are controlled via
.Ic set
and
.Ic unset
commands.
Options may be either binary, in which case it is only
significant to see whether they are set or not; or string, in which
case the actual value is of interest.
The binary options include the following:
.Bl -tag -width append
.It Ar append
Causes messages saved in
.Ar mbox
to be appended to the end rather than prepended.
This should always be set (perhaps in
.Pa /etc/mail.rc ) .
.It Ar ask, asksub
Causes
.Nm mail
to prompt you for the subject of each message you send.
If
you respond with simply a newline, no subject field will be sent.
.It Ar askcc
Causes you to be prompted for additional carbon copy recipients at the
end of each message.
Responding with a newline indicates your
satisfaction with the current list.
.It Ar askbcc
Causes you to be prompted for additional blind carbon copy recipients at the
end of each message.
Responding with a newline indicates your
satisfaction with the current list.
.It Ar autoprint
Causes the
.Ic delete
command to behave like
.Ic dp
\- thus, after deleting a message, the next one will be typed
automatically.
.It Ar debug
Setting the binary option
.Ar debug
is the same as specifying a single
.Fl d
on the command line and causes
.Nm mail
to output information useful for debugging. Use of 
.Fl d
on the command line multiple times is required to increase verbosity.
At a verbosity level of two, all lookups of variables are displayed to
show when settings like
.Ar debug
are tested during use.
.It Ar dot
The binary option
.Ar dot
causes
.Nm mail
to interpret a period alone on a line as the terminator
of a message you are sending.
.It Ar hold
This option is used to hold messages in the system mailbox
by default.
.It Ar ignore
Causes interrupt signals from your terminal to be ignored and echoed as
@'s.
.It Ar ignoreeof
An option related to
.Ar dot
is
.Ar ignoreeof
which makes
.Nm mail
refuse to accept a control-d as the end of a message.
.Ar Ignoreeof
also applies to
.Nm mail
command mode.
.It Ar metoo
Usually, when a group is expanded that contains the sender, the sender
is removed from the expansion.
Setting this option causes the sender
to be included in the group.
.It Ar noheader
Setting the option
.Ar noheader
is the same as giving the
.Fl N
flag on the command line.
.It Ar nosave
Normally, when you abort a message with two
.Tn RUBOUT
(erase or delete)
.Nm mail
copies the partial letter to the file
.Dq Pa dead.letter
in your home directory.
Setting the binary option
.Ar nosave
prevents this.
.It Ar Replyall
Reverses the sense of
.Ic reply
and
.Ic Reply
commands.
.It Ar quiet
Suppresses the printing of the version when first invoked.
.It Ar searchheaders
If this option is set, then a message-list specifier in the form ``/x:y''
will expand to all messages containing the substring ``y'' in the header
field ``x''.  The string search is case insensitive. Regardless of this
setting, ``%x:y'' will search in this fashion.
.It Ar verbose
Setting the option
.Ar verbose
is the same as using the
.Fl v
flag on the command line.
When mail runs in verbose mode,
the actual delivery of messages is displayed on the user's
terminal.
.El
.Ss Option String Values
.Bl -tag -width Va
.It Ev EDITOR
Pathname of the text editor to use in the
.Ic edit
command and
.Ic \&~e
escape.
If not defined, then a default editor is used.
.It Ev LISTER
Pathname of the directory lister to use in the
.Ic folders
command.
Default is
.Pa /bin/ls .
.It Ev MBOX
The name of the
.Ar mbox
file.
It can be the name of a folder.
The default is
.Dq Li mbox
in the user's home directory.
.It Ev PAGER
Pathname of the program to use in the
.Ic more
command or when
.Ic crt
variable is set.
The default paginator
.Xr more 1
is used if this option is not defined.
.It Ar RNMAIL
Holds the name of the external mailer for the
.Ic Rnmail
command.
.It Ev SHELL
Pathname of the shell to use in the
.Ic \&!
command and the
.Ic \&~!
escape.
A default shell is used if this option is
not defined.
.It Ev VISUAL
Pathname of the text editor to use in the
.Ic visual
command and
.Ic \&~v
escape.
.It Va charset
When
.Va charset
has the name of a MIME charset, MIME-words in subject headers will
be decoded for display in the list view if they are a matching charset.
See RFC-2047 for the full specification but in general they look like
.Ic =?CHARSET?Q?Some_Content_Here?=
.It Va crt
The valued option
.Va crt
is used as a threshold to determine how long a message must
be before
.Ev PAGER
is used to read it.
If
.Va crt
is set without a value,
then the height of the terminal screen stored in the system
is used to compute the threshold (see
.Xr stty 1 ) .
.It Ar endhlstr
A suffix to be displayed after headers in the 
.Ic highlight 
list.
.It Ar escape
If defined, the first character of this option gives the character to
use in the place of ~ to denote escapes.
.It Ar folder
The name of the directory to use for storing folders of
messages.
If this name begins with a `/',
.Nm mail
considers it to be an absolute pathname; otherwise, the
folder directory is found relative to your home directory.
.It Ar indentprefix
String used by the ``~m'' tilde escape for indenting messages, in place of
the normal tab character (^I).
Be sure to quote the value if it contains
spaces or tabs.
.It Ar record
If defined, gives the pathname of the file used to record all outgoing
mail.
If not defined, then outgoing mail is not so saved.
.It Ar starthlstr
A prefix to be displayed before headers in the 
.Ic highlight 
list.
.It Ar toplines
If defined, gives the number of lines of a message to be printed out
with the
.Ic top
command; normally, the first five lines are printed.
.El
.Sh ENVIRONMENT
.Nm Mail
utilizes the
.Ev HOME
and
.Ev USER
environment variables.
.Sh FILES
.Bl -tag -width /usr/lib/mail.*help -compact
.It Pa /var/spool/mail/*
Post office.
.It ~/mbox
User's old mail.
.It ~/.mailrc
File giving initial mail commands.
.It Pa /tmp/R*
Temporary files.
.It Pa /usr/lib/mail.*help
Help files.
.It Pa /etc/mail.rc
System initialization file.
.El
.Sh SEE ALSO
.Xr Rnmail 1 ,
.Xr trn 1 ,
.Xr fmt 1 ,
.Xr newaliases 1 ,
.Xr vacation 1 ,
.Xr aliases 5 ,
.Xr mailaddr 7 ,
.Xr sendmail 8
and
.Rs
.%T "The Mail Reference Manual" .
.Re
.Sh HISTORY
A
.Nm mail
command
appeared in
.At v6 .
This man page is derived from
.%T "The Mail Reference Manual"
originally written by Kurt Shoens.
.Sh BUGS
There are some flags that are not documented here.
Most are
not useful to the general user.
.Pp
.\" This bug is not the case in this particular distribution.
.\" Usually, .Nm mail is just a link to .Nm Mail, which can be confusing.