SYNC(8)                 FreeBSD System Manager's Manual                SYNC(8)

NAME
     sync - force completion of pending disk writes (flush cache)

SYNOPSIS
     sync

DESCRIPTION
     The sync 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
     reboot(8) or halt(8).  Generally, it is preferable to use reboot(8) or
     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 sync.

     The sync utility utilizes the sync(2) function call.

SEE ALSO
     fsync(2), sync(2), syncer(4), halt(8), reboot(8)

HISTORY
     A sync utility appeared in Version 4 AT&T UNIX.

FreeBSD 13.1-RELEASE-p6          May 31, 1993          FreeBSD 13.1-RELEASE-p6