Score:0

Ubuntu

How to create a shadow directory

Paul A.

11/17/22, 7:03 PM

I want to create a shadow directory of a directory D. The shadow directory D1 should have the same structure as D, but should not share any nodes with D. Each file in D should be represented by a symlink to that file in D1. The idea is that operations on D1 should never modify D, so that I can freely delete anything in D1 without affecting D. How can I achieve this? I could of course do a simple tree copy of D but that would make duplicate copies of the files.

[The following was moved from a comment.] Here's what I want to achieve. I have some music files in scattered locations. I'm able to create a single directory, D, that contains symlinks to all of them. My plan is to create the shadow directory D1 that initially contains copies of D's symlinks. As I play music I delete its nodes from D1, so that D1 only contains pointers to the music I haven't played (at various levels in D). Meanwhile my original music library is unmodified. I realize there might be other ways to achieve the same thing, but this method is concreptually simple and should require only standard shell programming.

1 + 8

directory

symbolic-link

Nmath

11/17/22, 7:10 PM

What is a "shadow directory"? Can you be more specific and less cryptic about what you intend to do? It's not clear what you mean by your notation "D"?

Rinzwind

11/17/22, 7:16 PM

"but that would make duplicate copies of the files." and "The idea is that operations on D1 should never modify D" are contradictions.

heynnema

11/17/22, 7:56 PM

This isn't a Ubuntu question... but rather a Windows question.

waltinator

11/17/22, 7:58 PM

Seems like a silly idea - why wouldn't a version control system (`rcs`, `git`, `sccs`, ...) do the trick? However, if you're stuck on that idea, read `man inotify`.

Paul A.

11/18/22, 4:59 AM

Here's what I want to achieve . I have some music files in scattered locations. I'm able to create a single directory, D, that contains symlinks to all of them. My plan is to create the shadow directory D1 that initially contains copies of D's symlinks. As I play music I delete its nodes from D1, so that D1 only contains pointers to the music I haven't played (at various levels in D). Meanwhile my original music library is unmodified. I realize there might be other ways to achieve the same thing, but this method is concreptually simple and should require only standard shell programming.

vanadium

11/18/22, 9:44 AM

Rather than explaining in a comment, explain in your actual question - use edit. Comments may not be read or may disappear. What are "nodes" for you? How do you delete them? I only can delete files, folders or symlinks. I am afraid you are having an XY problem and that there are better ways to achieve what you want. A mirror copy of hard linked files, for example.

Paul A.

11/19/22, 7:39 PM

A version control system isn't really appropriate, because changes to the music library are purely additive. I hardly ever change something that's already there. I'm not expecting to add much more music to it.

Paul A.

11/19/22, 7:43 PM

Windows is not relevant here, since I'm doing everything under Linux, and for simplicity I want to do it all using the shell.

Score:1

Ubuntu

Martin Thornton

11/17/22, 10:23 PM

As well as by using ln, you can also make symbolic links to files with cp by using the -s flag. This is useful, because this still works with the -r and -a flags, meaning you can clone an entire tree of symlinks, from D to D1.

To work correctly, D must be an absolute path, or converted to one by using $(realpath D).

Putting this all together:

cp -asT "$(realpath D)" D1

To be clear, editing files in D1 will still change the originals in D, but links in D1 can be safely deleted.

0 + 0

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: How to create a shadow directory

TH: วิธีสร้างไดเร็กทอรีเงา

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RU: Как создать теневой каталог

VI: Cách tạo một thư mục bóng tối

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