update.8

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)update.8	8.2	12/3/90
.TH update 8 
.SH Name
update \- periodically update the super block
.SH Syntax
.B /etc/update 
[ \fIseconds\fR ]
.SH Description
The
.PN update
program executes
the 
.MS sync 2
primitive every 30 seconds.
This insures that the file system
is fairly up to date in case of a crash.
This command should not be executed directly.
Rather, it should be executed out of the
initialization shell command file.
.SH Options
.IP \fIseconds\fR 12
Changes the sync period from the default of 30 seconds to a
period between 10 and 600 seconds. The \fIseconds\fR argument is a whole
number between 10 and 600. 
.NXR "update program"
.NXAM "sync system call" "update program"
.NXR "superblock" "updating"
.SH See Also
sync(1), sync(2), init(8), rc(8),