Differential D21660 Diff 62105 bin/sync/sync.8

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	.\" 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.
	.\"			.\"
	.\" @(#)sync.8 8.1 (Berkeley) 5/31/93			.\" @(#)sync.8 8.1 (Berkeley) 5/31/93
	.\" $FreeBSD$			.\" $FreeBSD$
	.\"			.\"
	.Dd May 31, 1993			.Dd September 14, 2019
	.Dt SYNC 8			.Dt SYNC 8
	.Os			.Os
	.Sh NAME			.Sh NAME
	.Nm sync			.Nm sync
	.Nd force completion of pending disk writes (flush cache)			.Nd force completion of pending disk writes (flush cache)
	.Sh SYNOPSIS			.Sh SYNOPSIS
	.Nm			.Nm
				.Op Ar number
				.Nm
				.Op arg
	.Sh DESCRIPTION			.Sh DESCRIPTION
	The			The
	.Nm			.Nm
	utility			utility
	can be called to ensure that all disk writes have been completed before the			can be called to ensure that all disk writes have been completed before the
	processor is halted in a way not suitably done by			processor is halted in a way not suitably done by
	.Xr reboot 8			.Xr reboot 8
	or			or
	.Xr halt 8 .			.Xr halt 8 .
	Generally, it is preferable to use			Generally, it is preferable to use
	.Xr reboot 8			.Xr reboot 8
	or			or
	.Xr halt 8			.Xr halt 8
	to shut down the system,			to shut down the system,
	as they may perform additional actions			as they may perform additional actions
	such as resynchronizing the hardware clock			such as resynchronizing the hardware clock
	and flushing internal caches before performing a final			and flushing internal caches before performing a final
	.Nm .			.Nm .
	.Pp			.Pp
	The			The
	.Nm			.Nm
	utility utilizes the			utility utilizes the
	.Xr sync 2			.Xr sync 2
	function call.			function call.
				.Pp
				If
				.Nm
				is given a single numeric argument, it will call the
				.Xr sync 2
				function call that number of times; if it is given a non-numeric
				argument, or the number is 0 or negative, then
				.Nm
				will call the
				.Xr sync 2
				function call once for each argument, and one additional time.
				.Sh EXAMPLES
				Call the
				.Xr sync 2
				function once:
				.Dl $ sync
				.Pp
				Call the
				.Xr sync 2
				function three times:
				.Dl $ sync 3
				or:
				.Dl $ sync sync sync
	.Sh SEE ALSO			.Sh SEE ALSO
	.Xr fsync 2 ,			.Xr fsync 2 ,
	.Xr sync 2 ,			.Xr sync 2 ,
	.Xr syncer 4 ,			.Xr syncer 4 ,
	.Xr halt 8 ,			.Xr halt 8 ,
	.Xr reboot 8			.Xr reboot 8
	.Sh HISTORY			.Sh HISTORY
	A			A
	.Nm			.Nm
	utility appeared in			utility appeared in
	.At v4 .			.At v4 .