need help making hard link for a directory tree

I need to mirror a complex directory structure with hard links. Of course the
directories themselves can not be hard linked, but is there a simple way to
create a duplicate directory tree and then make hard links to all of the
files?

The links are to provide ftp access to files in a chrooted area on the same
partition.


Thanks.

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fedora-list@jamesplace.net wrote:
> I need to mirror a complex directory structure with hard links. Of course the
> directories themselves can not be hard linked, but is there a simple way to
> create a duplicate directory tree and then make hard links to all of the
> files?
>
> The links are to provide ftp access to files in a chrooted area on the same
> partition.

Try this script. Run it from the top-level directly that you want to
copy-by-linking, after setting the CHROOT value to the full pathname of
the directory you want to create the copy in. This script will only link
regular files, not symlinks, device files etc., but you should be able
to modify it to do that fairly easily if you need to do that.

#!/bin/sh

# TEMPLATE directory is root of tree you want to replicate.
# It should *not* be an absolute pathname.
TEMPLATE=.

# CHROOT is absolute pathname of directory you want to clone the
# template to.
# It must be an absolute pathname and it must not be a subdirectory
# of the template directory.
CHROOT=/path/to/chroot

# Replicate directory structure
find $TEMPLATE -type d -exec mkdir -p $CHROOT/{} \;

# Make hard links to files
find $TEMPLATE -type f -exec ln {} $CHROOT/{} \;



Paul.

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On Mon, 14 Feb 2005 08:14:59 -0600, fedora-list@jamesplace.net
<fedora-list@jamesplace.net> wrote:
> I need to mirror a complex directory structure with hard links. Of course the
> directories themselves can not be hard linked,


Actually, you *can* hard-link directories (if root). But it's just
not advisable
unless you are an *expert*. Hard linked directories can cause all kinds of
strangeness, and potentially corrupted filesystems. In addition the meaning
of "." and ".." may be surprising to you, or to some software. [in fact the
"." and ".." directories are in fact just hard links to the real
directory, which the
kernel creates for you automatically.]

See the man page for ln(1), and for link(2).


> but is there a simple way to
> create a duplicate directory tree and then make hard links to all of the
> files?

Many options...

The -l option on the cp(1) command.

Use a gtar-pair with the -H option, like,

gtar -C srcdir -cHf - . | gtar -C destdir -xHpf -

Use rsync, like,

rsync -av /srcdir /destdir

(It's really the -l option on rsync, but the -a implies -l)

Or, if you want symlinks instead of hardlinks, see the
lndir(1) command.


> The links are to provide ftp access to files in a chrooted area on the same
> partition.

Then another option, is to use loopback mounts. That has the advantage in
that files can be added/removed without having to redo link maintenance.

--
Deron Meranda

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This worked brilliantly. I was able to modify the script a little and it works
very well.
I just delete the entire (destination) structure each night, and re-create it
with the script to account for the occasional/rare file rename/delete.

It was hard links to directories that I thought it best to avoid.
This was very helpful.

Thanks much.

===

On Mon February 14 2005 8:31 am, Paul Howarth wrote:
> fedora-list@jamesplace.net wrote:
> > I need to mirror a complex directory structure with hard links. Of course
> > the directories themselves can not be hard linked, but is there a simple
> > way to create a duplicate directory tree and then make hard links to all
> > of the files?
> >
> > The links are to provide ftp access to files in a chrooted area on the
> > same partition.
>
> Try this script. Run it from the top-level directly that you want to
> copy-by-linking, after setting the CHROOT value to the full pathname of
> the directory you want to create the copy in. This script will only link
> regular files, not symlinks, device files etc., but you should be able
> to modify it to do that fairly easily if you need to do that.
>
> #!/bin/sh
>
> # TEMPLATE directory is root of tree you want to replicate.
> # It should *not* be an absolute pathname.
> TEMPLATE=.
>
> # CHROOT is absolute pathname of directory you want to clone the
> # template to.
> # It must be an absolute pathname and it must not be a subdirectory
> # of the template directory.
> CHROOT=/path/to/chroot
>
> # Replicate directory structure
> find $TEMPLATE -type d -exec mkdir -p $CHROOT/{} \;
>
> # Make hard links to files
> find $TEMPLATE -type f -exec ln {} $CHROOT/{} \;
>
>
>
> Paul.

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