115 lines
3.3 KiB
Groff
115 lines
3.3 KiB
Groff
.\" $NetBSD: flock.1,v 1.13 2019/10/04 16:14:05 uwe Exp $
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.\"
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.\" Copyright (c) 2012 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Christos Zoulas.
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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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\"
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.Dd October 4, 2019
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.Dt FLOCK 1
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.Os
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.Sh NAME
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.Nm flock
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.Nd Provide locking API for shell scripts
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.Sh SYNOPSIS
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.\"
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.Nm
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.Op Fl dnosvx
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.Op Fl w Ar timeout
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.Ar file Ns \^|\^ Ns Ar directory
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.Ar command
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.Op Ar args No ...
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.\"
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.Nm
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.Op Fl dnosvx
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.Op Fl w Ar timeout
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.Ar file Ns \^|\^ Ns Ar directory
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.Fl c Ar command
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.\"
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.Nm
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.Op Fl dnsuvx
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.Op Fl w Ar timeout
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.Ar number
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.Sh DESCRIPTION
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The
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.Nm
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utility provides
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.Xr flock 2
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access to the command line or scripts.
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The first two forms lock the specified
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.Ar file
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or
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.Ar directory
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while the provided command is executed.
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If the path does not exist, then a file of that name is created with
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mode 0600.
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.Pp
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The third form can use an arbitrary file descriptor
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.Ar number
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that is provided from a shell script for example:
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.Bd -literal -offset indent
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(
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flock -s 100
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# commands to be executed under the lock
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) 100> /path/to/lockfile
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.Ed
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.Pp
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The following options are available:
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.Bl -tag -width Fl
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.It Fl c Ar command
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Pass a command to a the shell.
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.It Fl d , Fl Fl debug
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Provide debugging output.
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.It Fl n , Fl Fl nb , Fl Fl nonblock
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Don't block and fail immediately if the lock could not be obtained.
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.It Fl o , Fl Fl close
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Close the file before executing the command.
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This is useful if the child forks and should not be holding the lock.
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.It Fl s , Fl Fl shared
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Obtain a shared lock.
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.It Fl u , Fl Fl unlock
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Unlock an existing lock.
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This is available only for a file descriptor.
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.It Fl v , Fl Fl verbose
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On error print an explanation of the failure.
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.It Fl w , Fl Fl wait , Fl Fl timeout Ar seconds
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Fail if the lock could not be obtained after
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.Ar seconds .
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.It Fl x , Fl Fl exclusive
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Obtain an exclusive lock.
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This is the default.
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.El
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.Sh EXIT STATUS
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.Ex -std
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.Sh SEE ALSO
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.Xr shlock 1 ,
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.Xr flock 2
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.Sh HISTORY
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An
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.Nm
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utility appeared in
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.Nx 6.1 .
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