document /usr/share/misc/airport contents and rules, after lengthy

hackroom discussion about train stations.
ok mlarkin, feedback deraadt

diff --git a/share/man/man7/airport.7 b/share/man/man7/airport.7
new file mode 100644 (file)
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+.\"    $OpenBSD: airport.7,v 1.1 2017/05/28 19:26:33 benno Exp $
+.\"
+
+.\" Copyright (c) 2017 Sebastian Benoit.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd $Mdocdate: May 28 2017 $
+.Dt AIRPORT 7
+.Os
+.Sh NAME
+.Nm airport
+.Nd List of IATA airport codes
+.Sh DESCRIPTION
+The
+.Nm
+file is a list of airports that have an IATA airport code.
+The list is sorted alphabetically by airport code.
+.Pp
+The list is not a complete list of all IATA codes.
+New airports can only be added by
+.Ox
+developers who have visited an airport and thereby have verified its existence.
+.Sh CAVEATS
+There are also railway stations with IATA codes.
+These may not be listed, except if someone landed there by plane and
+survived to update the file.
+.Sh STANDARDS
+.Lk http://www.iata.org/codes
+.%T Airline and Airport Code Search
+.Sh FILES
+.Bl -tag -width /usr/share/misc/airport -compact
+.It Pa /usr/share/misc/airport
+.El