Strange ._ files

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Level 1

5 points

Strange ._ files

Hi.

I'm using tar to create a tape archive. I have a list of the to be backupped files in a seperate file and then call:

tar cvf backup.tar -T files.txt

While the backup ran, I saw:

…
./. IMG0123.JPG
./IMG_0123.JPG
./. IMG0124.JPG
./IMG_0124.JPG
…

Skwars-MacBook-Pro:DCIM alex$ grep _0124 files.txt
./IMG_0124.JPG

This shows, that in files.txt, there's only "./IMG_0124.JPG".

But why did that "./. IMG0124.JPG" get included?

$ tar tvf backup.tar ' IMG_0124'
-rw-r--r-- alex/staff 53466 2009-07-07 19:13:32 ./. IMG0124.JPG
-rw-r--r-- alex/staff 657838 2009-07-07 19:13:32 ./IMG_0124.JPG

So it indeed got included in the backup.

Why?

Thanks a lot,
Alexander

MacBook Pro, Mac OS X (10.5.7)

Posted on Jul 18, 2009 7:31 AM

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Answer 1

Best reply

Jeffrey Jones2

Level 6

8,660 points

Jul 18, 2009 8:24 AM in response to alexs77

If a file has extended attributes (use *+ls -l@+* to check), they are put into ._ files.

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Answer 2

Jul 18, 2009 8:25 AM in response to alexs77

I believe those are resource fork/hfs meta data files. If you don't want to deal with those, you might try --exclude '\._*'
--
Cole

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Answer 3

alexs77 Author

Level 1

5 points

Jul 18, 2009 8:40 AM in response to Jeffrey Jones2

Aha.

ls -l@ revealed:

-rw-r--r--@ 1 alex staff 2044253 5 Jun 21:47 P1010429.JPG
com.apple.metadata:kMDItemSupportFileType 70

(Yes, different file, same "issue" G)

Where did that come from, and why do only some files have that?

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Answer 4

alexs77 Author

Level 1

5 points

Jul 18, 2009 8:42 AM in response to Cole Tierney

Doesn't work 😟

Skwars-MacBook-Pro:Garten #01 alex$ tar cvf /tmp/sdff.tar --exclude '\._*' .
./
…
./._P1010429.JPG
./P1010429.JPG
…

Skwars-MacBook-Pro:Garten #01 alex$ ls -la ./._P1010429.JPG
ls: ./._P1010429.JPG: No such file or directory

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Answer 5

Jul 18, 2009 9:31 AM in response to alexs77

kMDItem* is Spotlight metadata. You can use the mdls command to examine Spotlight data. I am not familiar with kMDItemSupportFileType.

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Answer 6

etresoft

Level 8

46,482 points

Jul 18, 2009 2:11 PM in response to alexs77

I believe this is part of Apple's version of TAR. I treats a TAR archive like a non-HFS+ file system.

There may be a more elegant solution, and I would love to know about it. But what I did was download the source to tar and just built my own version.

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Answer 7

Tony T1

Level 6

10,232 points

Jul 19, 2009 7:01 AM in response to etresoft

In Bash (Terminal), try: export COPY EXTENDED_ATTRIBUTESDISABLE=true

Another way (as etresoft said) is to just install the current version of GNU tar ( http://www.gnu.org/software/tar/ ). Then you will have both Tar's on your system (GNU will be in /usr/local/bin). You can also use a 3rd party archive program (such as Springy)

Yes, this is Apple's implementation of TAR. Unless you're sending these files to a non-Mac user (i.e. Windows), you should use Apple Tar. Without it, you will lose information, such as icons. (for example, a sparse archive will be viewed in finder as a directory)

See Wikipedia for an explanation of resource forks

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Answer 8

j.v.

Level 5

4,155 points

Jul 19, 2009 7:01 PM in response to alexs77

Those single quotes may be forcing the shell to interpret the \ and the * as literal characters rather than as an escape character and a globbing character. No, I haven't tried it, but you might try using double quotes (") instead of single quotes ('). And I'm not convinced that an escape backslash belongs there, either. So, you might see if --exclude "._*" does it.

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Answer 9

Tony T1

Level 6

10,232 points

Jul 20, 2009 11:02 AM in response to j.v.

I don't believe that its possible to exclude resource forks that way.
For TAR, just set the following variable: export COPY EXTENDED_ATTRIBUTESDISABLE=true

edit: seems that this changed in Leopard, try export COPYFILE_DISABLE=true

see Removing ._ (dot underscore) files on Leopard

Message was edited by: Tony T1

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