1.\" 2.\" Copyright (C) 1998 John D. Polstra. 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.\" 13.\" THIS SOFTWARE IS PROVIDED BY JOHN D. POLSTRA AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL JOHN D. POLSTRA OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/usr.bin/lockf/lockf.1,v 1.7.2.4 2002/06/21 15:27:51 charnier Exp $ 26.\" $DragonFly: src/usr.bin/lockf/lockf.1,v 1.2 2003/06/17 04:29:28 dillon Exp $ 27.\" 28.Dd July 7, 1998 29.Os 30.Dt LOCKF 1 31.Sh NAME 32.Nm lockf 33.Nd execute a command while holding a file lock 34.Sh SYNOPSIS 35.Nm 36.Op Fl ks 37.Op Fl t Ar seconds 38.Ar file 39.Ar command 40.Op Ar arguments 41.Sh DESCRIPTION 42The 43.Nm 44utility acquires an exclusive lock on a 45.Ar file , 46creating it if necessary. 47While holding the lock, it executes a 48.Ar command 49with optional 50.Ar arguments . 51After the 52.Ar command 53completes, 54.Nm 55releases the lock, and removes the 56.Ar file 57unless the 58.Fl k 59option is specified. 60.Bx Ns -style 61locking is used, as described in 62.Xr flock 2 ; 63the mere existence of the 64.Ar file 65is not considered to constitute a lock. 66.Pp 67The following options are supported: 68.Bl -tag -width Fl 69.It Fl k 70Causes the lock file to be kept (not removed) after the command 71completes. 72.It Fl s 73Causes 74.Nm 75to operate silently. 76Failure to acquire the lock is indicated only in the exit status. 77.It Fl t Ar seconds 78Specifies a timeout for waiting for the lock. By default, 79.Nm 80waits indefinitely to acquire the lock. 81If a timeout is specified with this option, 82.Nm 83will wait at most the given number of 84.Ar seconds 85before giving up. A timeout of 0 may be given, in which case 86.Nm 87will fail unless it can acquire the lock immediately. 88.El 89.Pp 90In no event will 91.Nm 92break a lock that is held by another process. 93.Sh DIAGNOSTICS 94If 95.Nm 96successfully acquires the lock, it returns the exit status produced by 97.Ar command . 98Otherwise, it returns one of the exit codes defined in 99.Xr sysexits 3 , 100as follows: 101.Bl -tag -width F_CANTCREATX 102.It Dv EX_TEMPFAIL 103The specified lock file was already locked by another process. 104.It Dv EX_CANTCREAT 105The 106.Nm 107utility 108was unable to create the lock file, e.g., because of insufficient access 109privileges. 110.It Dv EX_USAGE 111There was an error on the 112.Nm 113command line. 114.It Dv EX_OSERR 115A system call (e.g., fork) failed unexpectedly. 116.El 117.Sh SEE ALSO 118.Xr flock 2 , 119.Xr sysexits 3 120.Sh HISTORY 121A 122.Nm 123utility first appeared in 124.Fx 2.2 . 125.Sh AUTHORS 126.An John Polstra Aq jdp@polstra.com . 127