How to clone/copy all file/directory attributes onto different file/directory?

Question

I want to copy the attributes (ownership, group, ACL, extended attributes, etc.) of one directory to another but not the directory contents itself.

This does not work:

cp -v --attributes-only A B
cp: omitting directory `A'           

Note: It does not have to be cp.

Solution 1

After quite a bit of trial and error on the commandline, I think I've found the answer. But it isn't a cp-related answer.

rsync -ptgo -A -X -d --no-recursive --exclude=* first-dir/ second-dir

This does:

-p, --perms                 preserve permissions
-t, --times                 preserve modification times
-o, --owner                 preserve owner (super-user only)
-g, --group                 preserve group
-d, --dirs                  transfer directories without recursing
-A, --acls                  preserve ACLs (implies --perms)
-X, --xattrs                preserve extended attributes
    --no-recursive          disables recursion

For reference

    --no-OPTION             turn off an implied OPTION (e.g. --no-D)
-r, --recursive             recurse into directories

Solution 2

chmod --reference=first-dir second-dir

Solution 3

rsync -aAX --exclude='*' src_dir/ dst_dir

where dst_dir - is a target dir. Or:

rsync -dADXgot src_dir dst_dir

where dst_dir - is a dir containing target dir, or a non-existing target dir.

From rsync man page:

    -a, --archive               archive mode; equals -rlptgoD (no -H,-A,-X)
        --exclude=PATTERN       exclude files matching PATTERN

    -d, --dirs                  transfer directories without recursing
    -p, --perms                 preserve permissions
    -A, --acls                  preserve ACLs (implies -p)
    -X, --xattrs                preserve extended attributes
    -o, --owner                 preserve owner (super-user only)
    -g, --group                 preserve group
        --devices               preserve device files (super-user only)
        --specials              preserve special files
    -D                          same as --devices --specials
    -t, --times                 preserve modification times

Comments

[lynxlynxlynx]

You did not pass -r, so it is ignoring directories. But I guess you want to copy only the attributes, not the contents? I can think of only ugly hacks. Also note that install can preserve SELinux contexts.

[Gilles 'SO- stop being evil']

possible duplicate of Clone ownership and permissions from another file?

[Grzegorz Wierzowiecki]

@Gilles, thank you for pointing to another topic. It solves part of problem: ownership and mode. What about extended attributes?

[Gilles 'SO- stop being evil']

@GrzegorzWierzowiecki I'm afraid very few tools support extended attributes. If they're important, use killermist's rsync suggestion.

[Grzegorz Wierzowiecki]

Btw. Here are nice examples where one may see xattrs in action: GUI of Dolphin in KDE: imgur.com/oguuJNm or URL from where file was downloaded set by browsers: references: gist.github.com/gwpl/a00e18bc150f1e3518335d13c5e46ad7 + freedesktop.org/wiki/CommonExtendedAttributes + vhanda.in/blog/2014/07/tagging-your-files

[Sohail Si]

Also see unix.stackexchange.com/questions/20645/… and askubuntu.com/questions/56792/…

[tripledes]

I think I misunderstood you, you don't need the contents, just the xattr. If it was for SELinux, you could use chcon referencing the original directory (A).

[Grzegorz Wierzowiecki]

-r implies copy of all subdirectories and files in them... I do not want to copy whole tree... I want to copy attributes for only one and only one directory - without affecting it's contents.

[killermist]

That last edit is definitely a hit there. With or without a / on the second-dir, that finally does exactly what is asked, it looks like.

[jw013]

The trailing slash only makes a difference on the first argument, not the second. It's explained in the 3rd or 4th paragraph of the USAGE section of the rsync(1) man page.

[Gilles 'SO- stop being evil']

My gut feeling to copy all directory attributes and no regular file would be rsync -a -AX --include='*/' --exclude='*'. I haven't tested.

[killermist]

@jw013 Thanks on helping get this answer dialed in. I tried SO many options on my little sandbox test environment, and kept coming close, but having some part of it not work right.

[Mat]

This won't work recursively, and I believe it will not copy ACLs or extended attributes.

[nass]

it is long , but it works ace!

[Haddad]

It's not supposed to be recursive: The OP asked for "not the directory contents itself", and the accepted answer tells rsync --no-recursive. The problem with this answer is that it doesn't do ACLs or XATTRs.

[G-Man Says 'Reinstate Monica']

So, you’re not just recommending somebody else’s method; you’re recommending somebody else’s program, right? That’s OK, but I just wasted five minutes searching for documentation on a little-known non-standard program. It would be nice if you stated more clearly that you are recommending that people download a little-known non-standard program.

[user2284570]

You forgot hard links.

[Alek]

These commands just copy permissions/ownership/attributes of a single directory, without content, please read OP question. Hard links are not relevant here.

[user2284570]

Correct. For me hard link or not is an attribute.

[Alek]

I'm not aware of the filesystems that support hard links to directories. Is there any? Since we are talking about directories, there's no need to specify -H, because the directory can't be a hard link, as far as I concerned. Correct me if I'm wrong.

[user2284570]

The ext4 version used by android uses some directory hard links on the /data partition (at least in the case of Samsung).

[Alek]

Thanks for the information. But I tend to disagree with you that hard link or not is an attribute, it is more related to the data structure/topology, rather than to attributes of the filesystem object. I think what you suggested is hardly desired in most cases, including OP's question, furthermore rsync does not supported that as far as I know.