.\"	$NetBSD: sync.8,v 1.16 2016/08/12 02:59:23 sevan Exp $
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.\"	@(#)sync.8	8.1 (Berkeley) 5/31/93
.\"
.Dd August 12, 2016
.Dt SYNC 8
.Os
.Sh NAME
.Nm sync
.Nd force completion of pending disk writes (flush cache)
.Sh SYNOPSIS
.Nm
.Sh DESCRIPTION
The
.Nm
program can be called to ensure that all disk writes have been
completed before the processor is halted in a way not suitably done by
.Xr reboot 8
or
.Xr halt 8 .
Generally, it is preferable to use
.Xr reboot 8
or
.Xr halt 8
to shut down the system,
as they may perform additional actions
such as resynchronizing the hardware clock
and flushing internal caches before performing a final
.Nm .
.Pp
The
.Nm
program simply invokes the
.Xr sync 2
system call.
.Sh SEE ALSO
.Xr fsync 2 ,
.Xr sync 2 ,
.Xr halt 8 ,
.Xr reboot 8
.Sh HISTORY
A
.Nm
command appeared in
.At v4 .