update.tproj/update.8

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  32 .\"     @(#)update.8    8.3 (Berkeley) 4/19/94
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  34 .Dd April 19, 1994
  35 .Dt UPDATE 8
  36 .Os
  37 .Sh NAME
  38 .Nm update
  39 .Nd flush internal filesystem caches to disk frequently
  40 .Sh SYNOPSIS
  41 .Nm update
  42 .Op Ar normal_interval Op Ar save_energy_interval
  43 .Sh DESCRIPTION
  44 The
  45 .Nm update
  46 command helps protect the integrity of disk volumes
  47 by flushing
  48 volatile cached filesystem data
  49 to disk at thirty second intervals.
  50 .Nm Update
  51 uses the
  52 .Xr sync 2
  53 function call to do the task.
  54 The normal_interval and save_energy_interval can be used to set the
  55 .Xr sync 2 interval in seconds of the normal case and the case where the computer is trying to save energy.
  56 .Pp
  57 .Nm Update
  58 is commonly invoked at startup time by
  59 .Xr rc 8
  60 when the system goes multi-user.
  61 .Sh SEE ALSO
  62 .Xr sync 2 ,
  63 .Xr fsck 8 ,
  64 .Xr init 8 ,
  65 .Xr rc 8 ,
  66 .Xr sync 8
  67 .Sh BUGS
  68 It is possible on some systems that a
  69 .Xr sync
  70 occurring simultaneously with a crash may cause
  71 file system damage. See
  72 .Xr fsck 8 .
  73 .Sh HISTORY
  74 An
  75 .Nm update
  76 command appeared in
  77 .At v6 .