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From: mouse@thunder.mcrcim.mcgill.edu (der Mouse)
Newsgroups: comp.unix.programmer
Subject: Re: backup and restore: what about device files?
Message-ID: <1991Jun1.213927.28705@thunder.mcrcim.mcgill.edu>
Date: 1 Jun 91 21:39:27 GMT
References: <1991May16.233149.15268@athena.mit.edu>
Distribution: usa
Organization: McGill Research Centre for Intelligent Machines
Lines: 29

In article <1991May16.233149.15268@athena.mit.edu>, mlevin@jade.tufts.edu writes:

> I would appreciate some advice about the following.  When you use a
> backup and restore utility on a Unix system, does it backup and
> restore device files?

That depends on the utility.  BSD dump, for example, does; tar does not
(in any incarnation I am aware of, at least).  Depending on what you
are trying to do, sometimes one behavior is appropriate, sometimes the
other.

> If so, any ideas on how?  Is the info given by stat() enough to
> recreate the device file (using makenod() or something) for a
> restore?

Yes.

> Any information on getting the attributes of and then re-creating
> device files would be reatly appreciated.

stat(2) (and lstat(2), if you have it) on a device file will return the
device major/minor numbers in the st_rdev element; to recreate it you
hand the device number to mknod(2).

					der Mouse

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