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.\"	@(#)sync.8	8.1 (Berkeley) 5/31/93
.\"
.Dd $Mdocdate: August 16 2016 $
.Dt SYNC 8
.Os
.Sh NAME
.Nm sync
.Nd force completion of pending disk writes (flush cache)
.Sh SYNOPSIS
.Nm sync
.Sh DESCRIPTION
The
.Nm
utility 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 sync .
.Pp
.Nm
utilizes the
.Xr sync 2
function.
.Sh SEE ALSO
.Xr fsync 2 ,
.Xr sync 2 ,
.Xr halt 8 ,
.Xr reboot 8
.Sh HISTORY
A
.Nm
command appeared in
.At v4 .