403 lines
10 KiB
Groff
403 lines
10 KiB
Groff
.\"
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.\" Copyright (c) 1997-2006 Erez Zadok
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.\" Copyright (c) 1989 Jan-Simon Pendry
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.\" Copyright (c) 1989 Imperial College of Science, Technology & Medicine
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.\" Copyright (c) 1989 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Jan-Simon Pendry at Imperial College, London.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgment:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" %W% (Berkeley) %G%
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.\"
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.\" $Id: amd.8,v 1.14.2.1 2006/01/02 18:48:23 ezk Exp $
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.\" $FreeBSD$
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.\"
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.Dd January 2, 2006
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.Dt AMD 8
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.Os
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.Sh NAME
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.Nm amd
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.Nd automatically mount file systems
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.Sh SYNOPSIS
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.Nm
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.Fl H
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.Nm
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.Op Fl F Ar conf_file
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.Nm
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.Op Fl nprvHS
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.Op Fl a Ar mount_point
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.Op Fl c Ar duration
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.Op Fl d Ar domain
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.Op Fl k Ar kernel-arch
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.Op Fl l Ar logfile
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.Op Fl o Ar op_sys_ver
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.Op Fl t Ar timeout.retransmit
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.Op Fl w Ar interval
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.Op Fl x Ar log-option
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.Op Fl y Ar YP-domain
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.Op Fl A Ar arch
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.Op Fl C Ar cluster-name
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.Op Fl D Ar option
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.Op Fl F Ar conf_file
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.Op Fl O Ar op_sys_name
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.Op Fl T Ar tag
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.Oo
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.Ar directory mapname
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.Op Fl map-options
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.Oc
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.Ar ...
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.Sh DESCRIPTION
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The
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.Nm
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utility
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is a daemon that automatically mounts file systems
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whenever a file or directory
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within that file system is accessed.
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File systems are automatically unmounted when they
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appear to be quiescent.
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.Pp
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The
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.Nm
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utility
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operates by attaching itself as an
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.Tn NFS
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server to each of the specified
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.Ar directories .
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Lookups within the specified directories
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are handled by
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.Nm ,
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which uses the map defined by
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.Ar mapname
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to determine how to resolve the lookup.
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Generally, this will be a host name, some file system information
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and some mount options for the given file system.
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.Pp
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In the first form depicted above,
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.Nm
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will print a short help string.
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In the second form, if no options are
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specified, or if the
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.Fl F
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is used,
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.Nm
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will read configuration parameters from the file
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.Ar conf_file
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which defaults to
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.Pa /etc/amd.conf .
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The last form is described below.
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.Sh OPTIONS
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.Bl -tag -width indent
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.It Fl a Ar temporary-directory
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Specify an alternative location for the real mount points.
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The default is
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.Pa /.amd_mnt .
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.It Fl c Ar duration
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Specify a
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.Ar duration ,
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in seconds, that a looked up name remains
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cached when not in use.
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The default is 5 minutes.
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.It Fl d Ar domain
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Specify the local domain name.
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If this option is not
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given the domain name is determined from the hostname.
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.It Fl k Ar kernel-arch
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Specifies the kernel architecture.
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This is used solely
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to set the ${karch} selector.
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.It Fl l Ar logfile
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Specify a logfile in which to record mount and unmount events.
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If
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.Ar logfile
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is the string
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.Dq Li syslog ,
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then the log messages will be sent to the system log daemon by
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.Xr syslog 3 .
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The default syslog facility used is
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.Dv LOG_DAEMON .
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If you
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wish to change it, append its name to the log file name, delimited by a
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single colon.
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For example, if
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.Ar logfile
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is the string
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.Dq Li syslog:local7
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then
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.Nm
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will log messages via
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.Xr syslog 3
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using the
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.Dv LOG_LOCAL7
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facility (if it exists on the system).
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.It Fl n
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Normalize hostnames.
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The name referred to by ${rhost} is normalized relative to the
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host database before being used.
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The effect is to translate
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aliases into
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.Dq official
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names.
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.It Fl o Ar op_sys_ver
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Override the compiled-in version number of the operating system.
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Useful
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when the built in version is not desired for backward compatibility reasons.
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For example, if the build in version is
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.Dq Li 2.5.1 ,
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you can override it to
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.Dq Li 5.5.1 ,
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and use older maps that were written with the latter in mind.
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.It Fl p
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Print PID.
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Outputs the process ID of
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.Nm
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to standard output where it can be saved into a file.
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.It Fl r
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Restart existing mounts.
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The
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.Nm
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utility
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will scan the mount file table to determine which file systems
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are currently mounted.
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Whenever one of these would have
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been auto-mounted,
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.Nm
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.Em inherits
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it.
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.It Fl t Ar timeout.retransmit
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Specify the NFS
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.Ar timeout
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interval,
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in tenths of a second, between
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.Tn NFS/RPC
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retries (for UDP only).
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The default
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is 0.8 seconds.
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The second value alters the retransmit counter, which
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defaults to 11 retransmissions.
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Both of these values are used by the kernel
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to communicate with amd.
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Useful defaults are supplied if either or both
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values are missing.
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.Pp
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The
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.Xr amd 8
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utility
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relies on the kernel RPC retransmit mechanism to trigger mount retries.
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The values of these parameters change the overall retry interval.
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Too long
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an interval gives poor interactive response; too short an interval causes
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excessive retries.
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.It Fl v
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Version.
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Displays version and configuration information on standard error.
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.It Fl w Ar interval
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Specify an
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.Ar interval ,
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in seconds, between attempts to dismount
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file systems that have exceeded their cached times.
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The default is 2 minutes.
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.It Fl x Ar options
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Specify run-time logging options.
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The options are a comma separated
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list chosen from:
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.Li fatal , error , user , warn , info , map , stats , all .
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.It Fl y Ar domain
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Specify an alternative
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.Tn NIS
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domain from which to fetch the
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.Tn NIS
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maps.
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The default is the system domain name.
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This option is ignored if
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.Tn NIS
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support is not available.
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.It Fl A Ar arch
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Specifies the OS architecture.
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This is used solely to set the ${arch}
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selector.
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.It Fl C Ar cluster-name
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Specify an alternative HP-UX cluster name to use.
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.It Fl D Ar option
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Select from a variety of debug options.
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Prefixing an
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option with the string
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.Dq Li no
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reverses the effect of that option.
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Options are cumulative.
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The most useful option is
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.Dq Li all .
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.Pp
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Since
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.Fl D
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is only used for debugging other options are not documented here:
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the current supported set of options is listed by the
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.Fl v
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option
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and a fuller description is available in the program source.
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.It Fl F Ar conf_file
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Specify an
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.Nm
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configuration file to use.
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See
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.Xr amd.conf 5
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for description of this file's format.
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This configuration file is used to
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specify any options in lieu of typing many of them on the command line.
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The
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.Xr amd.conf 5
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file includes directives for every command line option amd has, and many
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more that are only available via the configuration file facility.
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The
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configuration file specified by this option is processed after all other
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options had been processed, regardless of the actual location of this option
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on the command line.
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.It Fl H
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Print help and usage string.
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.It Fl O Ar op_sys_name
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Override the compiled-in name of the operating system.
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Useful when the
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built in name is not desired for backward compatibility reasons.
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For
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example, if the build in name is
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.Dq Li sunos5 ,
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you can override it to
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.Dq Li sos5
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and use older maps which were written with the latter in mind.
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.It Fl S
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Do not lock the running executable pages of
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.Nm
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into memory.
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To improve
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.Nm Ns 's
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performance, systems that support the
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.Xr plock 3
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call, could lock the
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.Nm
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process into memory.
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This way there is less chance
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the operating system will schedule, page out, and swap the
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.Nm
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process as
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needed.
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This tends to improve
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.Nm Ns 's
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performance, at the cost of reserving the
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memory used by the
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.Nm
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process (making it unavailable for other processes).
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If this behavior is not desired, use the
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.Fl S
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option.
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.It Fl T Ar tag
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Specify a tag to use with
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.Xr amd.conf 5 .
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All map entries tagged with
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.Ar tag
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will be processed.
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Map entries that are not tagged are always processed.
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Map entries that are tagged with a tag other than
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.Ar tag
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will not be processed.
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.El
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.Sh FILES
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.Bl -tag -width ".Pa /etc/amd.conf"
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.It Pa /.amd_mnt
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directory under which file systems are dynamically mounted
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.It Pa /etc/amd.conf
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default configuration file
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.El
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.Sh CAVEATS
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Some care may be required when creating a mount map.
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.Pp
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Symbolic links on an
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.Tn NFS
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file system can be incredibly inefficient.
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In most implementations of
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.Tn NFS ,
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their interpolations are not cached
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by the kernel and each time a symbolic link is encountered during a
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.Em lookuppn
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translation it costs an
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.Tn RPC
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call to the
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.Tn NFS
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server.
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It would appear that a large improvement in real-time
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performance could be gained by adding a cache somewhere.
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Replacing symlinks with a suitable incarnation of the auto-mounter
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results in a large real-time speedup, but also causes a large
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number of process context switches.
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.Pp
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A weird imagination is most useful to gain full advantage of all
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the features.
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.Sh SEE ALSO
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.Xr domainname 1 ,
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.Xr hostname 1 ,
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.Xr syslog 3 ,
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.Xr amd.conf 5 ,
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.Xr mtab 5 ,
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.Xr amq 8 ,
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.Xr mount 8 ,
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.Xr umount 8
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.Pp
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.Dq am-utils
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.Xr info 1
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entry.
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.Rs
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.%A Erez Zadok
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.%B "Linux NFS and Automounter Administration"
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.%O ISBN 0-7821-2739-8
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.%I Sybex
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.%D 2001
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.Re
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.Pp
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.Pa http://www.am-utils.org/
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.Rs
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.%T Amd \- The 4.4 BSD Automounter
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.Re
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.Sh HISTORY
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The
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.Nm
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utility first appeared in
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.Bx 4.4 .
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.Sh AUTHORS
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.An Jan-Simon Pendry Aq jsp@doc.ic.ac.uk ,
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Department of Computing, Imperial College, London, UK.
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.Pp
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.An Erez Zadok Aq ezk@cs.sunysb.edu ,
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Computer Science Department, Stony Brook
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University, Stony Brook, New York, USA.
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.Pp
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Other authors and contributors to am-utils are listed in the
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.Pa AUTHORS
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file distributed with am-utils.
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