1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)comsat.8 8.1 (Berkeley) 6/4/93 29.\" 30.Dd January 21, 2010 31.Dt COMSAT 8 32.Os 33.Sh NAME 34.Nm comsat 35.Nd biff server 36.Sh SYNOPSIS 37.Nm 38.Sh DESCRIPTION 39The 40.Nm 41utility is the server process which receives reports of incoming mail 42and notifies users if they have requested this service. 43The 44.Nm 45utility receives messages on a datagram port associated with the 46.Dq biff 47service 48specification (see 49.Xr services 5 50and 51.Xr inetd 8 ) . 52The one line messages are of the form: 53.Pp 54.D1 Ar user Ns @ Ns Ar mailbox Ns - Ns Ar offset Ns Op : Ns Ar mailbox-name 55.Pp 56If the 57.Ar user 58specified is logged in to the system and the associated terminal has 59the owner execute bit turned on (by a 60.Dq Nm biff Cm y ) , 61the 62.Ar offset 63is used as a seek offset into the appropriate mailbox file and 64the first 7 lines or 560 characters of the message are printed 65on the user's terminal. 66Lines which appear to be part of 67the message header other than the 68.Dq Li From , 69.Dq Li \&To , 70.Dq Li Date , 71or 72.Dq Li Subject 73lines are not included in the displayed message. 74.Pp 75If the 76.Ar user 77specified is logged in to the system and the associated terminal has 78the group execute bit turned on (by a 79.Dq Nm biff Cm b ) , 80two bell characters 81.Tn ( ASCII 82\\007) are printed on the user's terminal. 83.Pp 84If 85.Ar mailbox-name 86omitted, standard mailbox assumed. 87.Sh FILES 88.Bl -tag -width ".Pa /var/mail/user" -compact 89.It Pa /var/run/utx.active 90to find out who is logged on and on what terminals 91.It Pa /var/mail/user 92standard mailbox 93.El 94.Sh SEE ALSO 95.Xr biff 1 , 96.Xr inetd 8 97.Sh HISTORY 98The 99.Nm 100utility appeared in 101.Bx 4.2 . 102.Sh BUGS 103The message header filtering is prone to error. 104The density of the information presented is near the theoretical minimum. 105.Pp 106Users should be notified of mail which arrives on other 107machines than the one to which they are currently logged in. 108.Pp 109The notification should appear in a separate window so it 110does not mess up the screen. 111