SUMMARY: virtual files?

From: Greg Ulyatt <>
Date: Thu Aug 09 2001 - 07:49:00 EDT
Got quite a few responses to this, the main ones being people who
suggested the use of '/bin/cat' (which was not quite the issue at
hand :) )

Regardless, I had quite a few good answers, the just of them being
the following options:

a) replace with a new variant and use LD_PRELOAD variables
 (good idea, but hard to implement in this idea)

b) wait for the next gen of filesystems which can do this (IE xfs and
rieser4 have these capabilities)

c) use MULTICS :)

Just to clairifiy for those who were unclear of the idea, I've been
asked to
give an example of why this would be useful.

Take a group of disjoint servers, different disks, cpu's etc. I would
like to
have a central respoitory for NFS mounts which  can be pushed out to
servers so that you would have the files:

/etc/vfstab.nfs (lists all NFS mounts)
/etc/vfstab.local (lists local mounts)

Now, you need a /etc/vfstab which is a catanation of the 2 files. If
the idea were to work nicely, /etc/vfstab would never be written to,
only read from, while the .nfs and .local could be written to & read
Then, /etc/vfstab would contain all the information from local and nfs
and no direct editing of /etc/vfstab would be nessecary.
This would be an easy solution to an annoying problem, but it appears
is no way to pull it off right now in Solaris.

I will just have to go with the original plan, just putting the file

Thanks all for the help!

> I doubt that this is the proper name (in fact, if this idea even exists
> is doubtful), but I was wondering if anyone out there has heard of a way
> to do a virtual file? It's bascially a file, in the filesystem, that
> contains the contants of at least 2 other files, but it's a single file.
> For example:
> file1.txt has 1 line, "this is file1"
> file2.txt has 1 line, "this is file2"
> now, the virtual file (say, fileall.txt) is a merger of file1.txt and
> file2.txt, so this file would have the lines:
> "this is file1
> this is file2"
> As well, when file2 is edited, the changes should be reflected in the
> fileall file as it is a container for file1 and file2.
> Has anyone out there ever heard of software or a filesystem to do this?
> (Does this description make sense?)

Greg Ulyatt
UNIX Systems Administrator
High Wycombe, Bucks, UK
Received on Thu Aug 9 12:49:00 2001

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