Re: [gentoo-user] Recreating a directory structure and indicating a files presence

[Alan McKinnon]

On Thu, 20 Sep 2012 20:33:39 +0800
Andrew Lowe <agl@×××××××.au> wrote:

> Hi all,
> 	I have the situation where I have a large amount of data,
> many TB's, made up of many, many files. This information has now been
> archived but I've got people who want to be able to see what data
> does/does not exist, filling in gaps where they may exist.
>
> 	As this data used to be available/visible in a directory
> structure, ie via a file browser, I thought the easiest way for them
> to see if something existed would be to create a mirror of the
> directory structure and then populate this dir structure with 1 - 5
> byte files with the same name as the "real" data files that now
> reside in the archive. I've seen some scripts on the interweb that
> allow me to create the dir structure, but does anyone have any ideas
> how to do the creation of the "marker" files in the active file
> system?
>
> 	Just buying more hard disks and keeping the data on line also
> isn't an option.
>
> 	Any thoughts, greatly appreciated,
>
> 		Andrew
>

I don't understand why you specify 1-5 byte files. Those few bytes will
always be useless. Rather use 0-length files.

On the archive:

find /root/of/dir/structure -type d > dirs.txt
find /root/of/dir/structure -type f > files.txt

Copy those two files to the on-line system:

for I in `cat dirs.txt` ; do mkdir -p $I ; done
for I in `cat files.txt` ; do touch -p $I ; done

Do that in the appropriate top-level directory of course. You can
probably make it more efficient using decent options to xargs, but what
the hell, I'd do it as-is. It's a once off action and finding the xargs
man page will take longer than the mkdirs....

-- 
Alan McKinnon
alan.mckinnon@×××××.com