NAME
sync - update the super block

SYNOPSIS
/etc/sync

DESCRIPTION
Sync executes the sync system primitive. Sync can be called to
insure 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 or halt 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.

See sync(2) for details on the system primitive.

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