SYNC(8) BSD System Manager's Manual SYNC(8)
sync - force completion of pending disk writes (flush cache)
Sync can be called to insure that all disk writes have been completed be-
fore the processor is halted in a way not suitably done by reboot(8) or
halt(8). Generally, it is preferable to use reboot or halt to shut down
the system, as they may perform additional actions such as resynchroniz-
ing the hardware clock and flushing internal caches before performing a
Sync utilizes the sync(2) function call.
sync(2), fsync(2), halt(8), reboot(8), update(8)
A sync command appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution May 31, 1993 1