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.\"	from: @(#)mail.local.8	6.8 (Berkeley) 4/27/91
.\"	$Id: mail.local.8,v 1.12 1998/02/24 05:00:24 millert Exp $
.\"
.Dd April 27, 1991
.Dt MAIL.LOCAL 8
.Os
.Sh NAME
.Nm mail.local
.Nd store mail in a mailbox
.Sh SYNOPSIS
.Nm mail.local
.Op Fl L
.Op Fl l
.Op Fl f Ar from
.Op Fl H
.Ar user ...
.Sh DESCRIPTION
.Nm Mail.local
reads the standard input up to an end-of-file and appends it to each
.Ar user Ns 's
.Pa mail
file.
The
.Ar user
must be a valid user name.
.Pp
The options are as follows:
.Bl -tag -width xxxxxxx
.It Fl f Ar from
Specify the sender's name.
.It Fl l
For compatibility, request that
files named 
.Nm username.lock
be used for locking.  (This is the default behavior.)
.It Fl L
Request that
.Fn flock
be used for locking the mail spool rather than
.Nm username.lock .
.It Fl H
This mode is useful for a client mail program to attain proper locking.
In this mode
.Nm mail.local
(ignoring all other arguments) attains a
.Nm username.lock
for the calling user and retains it until stdin is closed or a signal
like SIGINT, SIGTERM, or SIGHUP is received.  If
.Nm mail.local
is able to create the lock file, ``1'' is written to stdout, otherwise
``0'' is written and an error message is written to stderr.
.El
.Pp
Individual mail messages in the mailbox are delimited by an empty
line followed by a line beginning with the string ``From ''.
A line containing the string ``From '', the sender's name and a time stamp
is prepended to each delivered mail message.
A blank line is appended to each message.
A greater-than character (``>'') is prepended to any line in the message
which could be mistaken for a ``From '' delimiter line.
.Pp
Significant efforts have been made to ensure that
.Nm mail.local
acts as securely as possible if the spool directory is mode 1777 or 755.
The default of mode 755 is more secure, but it prevents mail clients from using
all styles of locking.  The use of 1777 is more flexible in an NFS shared-spool
environment, thus many sites use it.  However it does carry some risks, such
as attackers filling the spool disk.  Some of these problems may be alleviated
by making the spool a separate filesystem, and placing quotas on it.
The use of any mode other than 1777 and 755 for the spool directory is
recommended against but may work properly.
.Pp
By default, mailbox locking is done with
.Nm username.lock
files. However, if the
.Fl L
flag is specified, the mailbox is exclusively locked with
.Xr flock 2
while mail is appended.
.Pp
If the ``biff'' service is returned by
.Xr getservbyname 3 ,
the biff server is notified of delivered mail.
.Pp
The
.Nm mail.local
utility exits 0 on success, and >0 if an error occurs.
.Sh ENVIRONMENT
.Bl -tag -width indent
.It Ev TZ
Used to set the appropriate time zone on the timestamp.
.El
.Sh FILES
.Bl -tag -width /tmp/local.XXXXXXXXXX -compact
.It Pa /tmp/local.XXXXXXXXXX
temporary files
.It Pa /var/mail/user
user's mailbox directory
.El
.Sh HISTORY
A superset of
.Nm mail.local
(handling mailbox reading as well as mail delivery)
appeared in
.At v7
as the program
.Nm mail .
.Sh BUGS
Since
.Xr sendmail 8
bases its idea of whether a message has been delivered or not
on the return value from
.Nm mail.local ,
using quotas in
.Pa /var/mail
can be problematic.  By default,
.Xr sendmail 8
will ask
.Nm mail.local
to deliver a message to multiple recipients if possible.  This
causes problems in a quota environment since a message may be
delivered to some users but not others due to disk quotas.
Even though the message was delivered to some of the recipients,
.Nm mail.local
will exit with an exit code > 0, causing
.Xr sendmail 8
to attempt redelivery later.  That means that some users will keep getting
the same message every time
.Xr sendmail 8
runs its queue.
.br
If you are running with disk quotas on
.Pa /var/mail
it is imperative that you unset the
.Dq m
mailer flag for the
.Sq local
mailer.  To do this, locate the line beginning with
.Dq Mlocal
in
.Pa /etc/sendmail.cf
and remove the
.Dq m
from the flags section, denoted by
.Dq F= .
Alternately, you can override the default mailer flags by adding
the line:
.Dl define(`LOCAL_MAILER_FLAGS', `rn9')dnl
to your
.Dq \.mc
file (this is the source file that is used to generate
.Pa /etc/sendmail.cf ) .
.Sh SEE ALSO
.Xr biff 1 ,
.Xr mail 1 ,
.Xr xsend 1 ,
.Xr flock 2 ,
.Xr getservbyname 3 ,
.Xr comsat 8 ,
.Xr sendmail 8