Differential D25205 Diff 73251 head/usr.bin/lockf/lockf.1

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	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)			.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT			.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY			.\" 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			.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	.\" SUCH DAMAGE.			.\" SUCH DAMAGE.
	.\"			.\"
	.\" $FreeBSD$			.\" $FreeBSD$
	.\"			.\"
	.Dd July 7, 1998			.Dd June 18, 2020
	.Dt LOCKF 1			.Dt LOCKF 1
	.Os			.Os
	.Sh NAME			.Sh NAME
	.Nm lockf			.Nm lockf
	.Nd execute a command while holding a file lock			.Nd execute a command while holding a file lock
	.Sh SYNOPSIS			.Sh SYNOPSIS
	.Nm			.Nm
	.Op Fl kns			.Op Fl kns
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	.Nm			.Nm
	to operate silently.			to operate silently.
	Failure to acquire the lock is indicated only in the exit status.			Failure to acquire the lock is indicated only in the exit status.
	.It Fl n			.It Fl n
	Causes			Causes
	.Nm			.Nm
	to fail if the specified lock			to fail if the specified lock
	.Ar file			.Ar file
	does not exist. If			does not exist.
				If
	.Fl n			.Fl n
	is not specified,			is not specified,
	.Nm			.Nm
	will create			will create
	.Ar file			.Ar file
	if necessary.			if necessary.
	.It Fl t Ar seconds			.It Fl t Ar seconds
	Specifies a timeout for waiting for the lock.			Specifies a timeout for waiting for the lock.
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	.Xr fork 2 )			.Xr fork 2 )
	failed unexpectedly.			failed unexpectedly.
	.It Dv EX_SOFTWARE			.It Dv EX_SOFTWARE
	The			The
	.Ar command			.Ar command
	did not exit normally,			did not exit normally,
	but may have been signaled or stopped.			but may have been signaled or stopped.
	.El			.El
				.Sh EXAMPLES
				The first job takes a lock and sleeps for 5 seconds in the background.
				The second job tries to get the lock and timeouts after 1 second (PID numbers
				will differ):
				.Bd -literal -offset indent
				$ lockf mylock sleep 5 & lockf -t 1 mylock echo "Success"
				[1] 94410
				lockf: mylock: already locked
				.Ed
				.Pp
				The first job takes a lock and sleeps for 1 second in the background.
				The second job waits up to 5 seconds to take the lock and echoes the message on
				success (PID numbers will differ):
				.Bd -literal -offset indent
				$ lockf mylock sleep 1 & lockf -t 5 mylock echo "Success"
				[1] 19995
				Success
				[1]+ Done lockf mylock sleep 1
				.Ed
	.Sh SEE ALSO			.Sh SEE ALSO
	.Xr flock 2 ,			.Xr flock 2 ,
	.Xr lockf 3 ,			.Xr lockf 3 ,
	.Xr sysexits 3			.Xr sysexits 3
	.Sh HISTORY			.Sh HISTORY
	A			A
	.Nm			.Nm
	utility first appeared in			utility first appeared in
	.Fx 2.2 .			.Fx 2.2 .
	.Sh AUTHORS			.Sh AUTHORS
	.An John Polstra Aq Mt jdp@polstra.com			.An John Polstra Aq Mt jdp@polstra.com