1997-03-12 21:50:06 +03:00
|
|
|
.\" Copyright (c) 1991, 1993
|
|
|
|
|
.\" The Regents of the University of California. All rights reserved.
|
1993-03-21 12:45:37 +03:00
|
|
|
.\"
|
|
|
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
|
|
|
.\" modification, are permitted provided that the following conditions
|
|
|
|
|
.\" are met:
|
|
|
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
|
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
|
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
|
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
|
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
|
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
|
|
|
.\" must display the following acknowledgement:
|
|
|
|
|
.\" This product includes software developed by the University of
|
|
|
|
|
.\" California, Berkeley and its contributors.
|
|
|
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
|
|
|
.\" may be used to endorse or promote products derived from this software
|
|
|
|
|
.\" without specific prior written permission.
|
|
|
|
|
.\"
|
|
|
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
|
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
|
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
|
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
|
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
|
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
|
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
|
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
|
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
|
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
|
|
|
.\" SUCH DAMAGE.
|
|
|
|
|
.\"
|
1997-03-12 21:50:06 +03:00
|
|
|
.\" @(#)update.8 8.3 (Berkeley) 4/19/94
|
1993-03-21 12:45:37 +03:00
|
|
|
.\"
|
1997-03-12 21:50:06 +03:00
|
|
|
.Dd April 19, 1994
|
1993-03-21 12:45:37 +03:00
|
|
|
.Dt UPDATE 8
|
|
|
|
|
.Os
|
|
|
|
|
.Sh NAME
|
|
|
|
|
.Nm update
|
|
|
|
|
.Nd flush internal filesystem caches to disk frequently
|
|
|
|
|
.Sh SYNOPSIS
|
|
|
|
|
.Nm update
|
|
|
|
|
.Sh DESCRIPTION
|
|
|
|
|
The
|
|
|
|
|
.Nm update
|
|
|
|
|
command helps protect the integrity of disk volumes
|
|
|
|
|
by flushing
|
1994-01-14 19:22:25 +03:00
|
|
|
volatile cached filesystem data
|
1993-03-21 12:45:37 +03:00
|
|
|
to disk at thirty second intervals.
|
|
|
|
|
.Nm Update
|
|
|
|
|
uses the
|
|
|
|
|
.Xr sync 2
|
|
|
|
|
function call to do the task.
|
|
|
|
|
.Pp
|
|
|
|
|
.Nm Update
|
|
|
|
|
is commonly invoked at startup time by
|
|
|
|
|
.Xr rc 8
|
|
|
|
|
when the system goes multi-user.
|
|
|
|
|
.Sh SEE ALSO
|
|
|
|
|
.Xr sync 2 ,
|
|
|
|
|
.Xr fsck 8 ,
|
|
|
|
|
.Xr init 8 ,
|
|
|
|
|
.Xr rc 8 ,
|
|
|
|
|
.Xr sync 8
|
|
|
|
|
.Sh BUGS
|
1997-03-12 21:50:06 +03:00
|
|
|
It is possible on some systems that a
|
1993-10-05 03:13:17 +03:00
|
|
|
.Xr sync
|
1997-03-12 21:50:06 +03:00
|
|
|
occurring simultaneously with a crash may cause
|
1993-03-21 12:45:37 +03:00
|
|
|
file system damage. See
|
|
|
|
|
.Xr fsck 8 .
|
|
|
|
|
.Sh HISTORY
|
|
|
|
|
An
|
|
|
|
|
.Nm update
|
|
|
|
|
command appeared in
|
|
|
|
|
.At v6 .
|
