Copyright (C) 1997 John D. Polstra. All rights reserved.

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$Id$

.Dd January 8, 1997 .Os FreeBSD .Dt LOCKF 1 .Sh NAME .Nm lockf .Nd execute a command while holding a file lock .Sh SYNOPSIS .Nm .Op Fl s .Op Fl t Ar seconds .Ar file .Ar command .Op Ar arguments .Sh DESCRIPTION The .Nm utility acquires an exclusive lock on a .Ar file , creating it if necessary. While holding the lock, it executes a .Ar command with optional .Ar arguments . After the .Ar command completes, .Nm releases the lock and removes the .Ar file . BSD-style locking is used, as described in .Xr flock 2 ; the mere existence of the .Ar file is not considered to constitute a lock.

p The following options are supported: l -tag -width Fl t Fl s Causes .Nm to operate silently. Failure to acquire the lock is indicated only in the exit status. t Fl t Ar seconds Specifies a timeout for waiting for the lock. By default, .Nm waits indefinitely to acquire the lock. If a timeout is specified with this option, .Nm will wait at most the given number of .Ar seconds before giving up. A timeout of 0 may be given, in which case .Nm will fail unless it can acquire the lock immediately. .El

p In no event will .Nm break a lock that is held by another process. .Sh DIAGNOSTICS If .Nm is unable to acquire the lock, it returns an exit status of 1. Otherwise, it returns the exit status produced by .Ar command . .Sh SEE ALSO .Xr flock 2 . .Sh AUTHORS John Polstra, .Aq jdp@polstra.com .