1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.roff% 5.\" 6.\" @(#)sync.8 6.4 (Berkeley) 06/23/92 7.\" 8.Dd 9.Dt SYNC 8 10.Os BSD 4 11.Sh NAME 12.Nm sync 13.Nd force completion of pending disk writes (flush cache) 14.Sh SYNOPSIS 15.Nm sync 16.Sh DESCRIPTION 17.Nm Sync 18can be called to insure that all disk writes have been completed before the 19processor is halted in a way not suitably done by 20.Xr reboot 8 21or 22.Xr halt 8 . 23Generally, it is preferable to use 24.Xr reboot 25or 26.Xr halt 27to shut down the system, 28as they may perform additional actions 29such as resynchronizing the hardware clock 30and flushing internal caches before performing a final 31.Nm sync . 32.Pp 33.Nm Sync 34utilizes the 35.Xr sync 2 36function call. 37.Sh SEE ALSO 38.Xr sync 2 , 39.Xr fsync 2 , 40.Xr halt 8 , 41.Xr reboot 8 , 42.Xr update 8 43.Sh HISTORY 44A 45.Nm sync 46command appeared in 47.At v6 . 48