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UPDATE(8)                 BSD System Manager's Manual                UPDATE(8)

NAME
     update -- flush internal filesystem caches to disk frequently

SYNOPSIS
     update [normal_interval [save_energy_interval]]

DESCRIPTION
     The update command helps protect the integrity of disk volumes by flushing volatile cached filesystem
     data to disk at thirty second intervals.  Update uses the sync(2) function call to do the task.  The
     normal_interval and save_energy_interval can be used to set the sync(2) interval in seconds of the
     normal case and the case where the computer is trying to save energy.

     Update is invoked at startup time by launchd(8) when the system goes multi-user.

SEE ALSO
     sync(2), fsck(8), launchd(8), sync(8)

BUGS
     It is possible on some systems that a sync occurring simultaneously with a crash may cause file system
     damage. See fsck(8).

HISTORY
     An update command appeared in Version 6 AT&T UNIX.

BSD                             April 19, 1994                             BSD