Removing all extended attributes from a directory tree

May 7th, 2008 · 24 Comments

Here’s a simple one-liner I came up with to remove all HFS+ extended attributes on all files and directories below the current one in Mac OS X. Useful before creating a tar file that will be shared with non-Mac users (tar in OSX will create additional “resource” files to store extended attributes, which when untared on a Mac will be correctly reinstated, but in other systems will leave spurious hidden files all over the place).


for i in $(ls -Rl@ | grep '^      ' | awk '{print $1}' | sort -u); \
   do echo Removing $i ... >&2;  \
   find . | xargs xattr -d $i 2>/dev/null ; done

The space after the caret in the grep command is produced by typing Ctrl-V and then Tab, to insert a Tab character.

Tags: howto · Mac · Tips & tricks

24 responses so far ↓

1 Dominik Hoffmann // Jun 6, 2008 at 8:42 pm

This only puts out the name of the attribute it’s supposed to remove, but doesn’t actually. I am running this in sudo mode.
2 Hitchhiker // Jun 7, 2008 at 8:52 am

Dominik: if you are typing “sudo” followed by the command shown, then only the first command (the “for” is executed as root, so the attributes will not be removed (the xargs command is the one that needs to be run as root). You need to enter a root shell (you could run “sudo bash”) and then type the command in that shell so that all the commands execute as root.
3 Dominik Hoffmann // Jun 7, 2008 at 1:11 pm

Hi Hitchhiker: I had executed the command inside a root shell, via sudo -s. — Dominik
4 Hitchhiker // Jun 7, 2008 at 4:06 pm

Do you get any errors when executing the command? I see nothing wrong in the command as shown, it should work properly.
5 Hitchhiker // Jun 7, 2008 at 4:07 pm

Dominik: you could try removing the “2> /dev/null” after the xattr command, to have errors shown on the terminal.
6 Dominik Hoffmann // Jun 9, 2008 at 12:25 am

This is what I see:

echo Removing com.apple.AddressBook.ImageTransform.ABClipRect_1 …
xargs: unterminated quote

Dominik Hoffmann
7 Hitchhiker // Jun 9, 2008 at 6:37 am

The “unterminated quote” message makes me think there is a filename in the tree you are processing that has a quote character (single or double quote) in it. You could try adding the -t option to xargs (xargs -t xattr .., still leaving out the “2> /dev/null”), which will print the commands it executes, and see which command is printed before the error.
8 Dominik Hoffmann // Jun 9, 2008 at 1:51 pm

xargs -t doesn’t output anything.
9 Dominik Hoffmann // Jun 9, 2008 at 3:32 pm

Okay, I made the working directory ~/.ssh/.

This time it worked:

echo Removing com.apple.metadata:_kTimeMachineNewestSnapshot …
xattr -d com.apple.metadata:_kTimeMachineNewestSnapshot . ./authorized_keys ./id_dsa ./id_dsa.pub ./known_hosts
echo Removing com.apple.metadata:_kTimeMachineOldestSnapshot …
xattr -d com.apple.metadata:_kTimeMachineOldestSnapshot . ./authorized_keys ./id_dsa ./id_dsa.pub ./known_hosts

However, with the working directory being ~ and the -R option removed from the ls instruction I have

xargs: unterminated quote
echo Removing com.apple.metadata:_kTimeMachineNewestSnapshot …
xargs: unterminated quote
echo Removing com.apple.metadata:_kTimeMachineOldestSnapshot …
xargs: unterminated quote
10 Dominik Hoffmann // Jun 9, 2008 at 3:57 pm

This entry in the macosx.com forums, http://macosx.com/forums/unix-x11/19015-xargs-grep.html, pointed me in the right direction. It suggests the use of the -0 option in xargs in conjunction with the -print0 primary in find. It therefore works, when I execute

for i in $(ls -Rl@ | grep ‘^ ‘ | awk ‘{print $1}’ | sort -u); do echo echo Removing $i … >&2; find . -print0 | xargs -0t xattr -d $i 2>/dev/null ; done

Now it would be interesting to know, why you guys don’t need those modifications and I do.

Dominik
11 Hitchhiker // Jun 9, 2008 at 11:43 pm

Dominik: I figured that was the problem. You must have some files with quote characters in them (or some other punctuation), which is why it doesn’t work with the standard separators.

Glad you got it to work!
12 PantherModem » Blog Archive » GCC Says: error: expected unqualified-id before ‘OTHER’ token // Jul 4, 2008 at 4:42 pm

[...] coming from files with extended attributes. I cleaned out all the extended attributes (thanks to Diego Zamboni’s script), but the error still remained. In the end the only thing that worked was to delete the erroneous [...]
13 Joseph // Jul 9, 2008 at 9:08 pm

Many thanks on putting this script together. Is there a way to prevent these extended attributes from being generated in the first place? I ask because I have never noticed this before upgrading to 10.5, and other computers using the 10.5 do not appear to create these extended attributes. I often tar directories containing 1000s of files, and the presence of extended attributes makes the compressing/decompressing very slow.
14 Justin Force // Nov 21, 2008 at 1:03 am

You can simplify this quite a lot.

find . -exec xattr -d {} ;

Doesn't give you the satisfying output, but it works.
15 Justin Force // Nov 21, 2008 at 1:09 am

Wait! No it doesn't. Wish I could delete that post…
16 zzamboni // Nov 21, 2008 at 8:50 am

Justin: it doesn't, because you have to give to xattr -d the attribute you want to delete. That's what the script does – first find all the attributes that exist under the directory, and then loop over them, removing them in sequence.
17 John Rikes // Apr 18, 2009 at 10:26 pm

Should this remove the info found in the "Get Info" menu item? After I ran this, I still see a URL from where I downloaded my files from…
18 Tyler Havener // May 6, 2009 at 10:49 pm

is there a reason why "echo" is listed twice?
19 zzamboni // May 8, 2009 at 7:21 am

It was a mistake. I have corrected it. Thanks for pointing it out!
20 A Friend // Jun 10, 2009 at 5:35 pm

It also might be worth mentioning that you can create copy of a file or directory that doesn't have any extended attributes by passing the -X option to the cp command.

For example, if you want to make a clean tar file of the directory "my_files", you could do the following:

# copy my_files to the Desktop, excluding extended attributes
cp -rX ~/Documents/my_files ~/Desktop/my_files

# go to Desktop
cd ~/Desktop

# create the tar file, excluding .DS_Store files
tar cjvf my_files.tar.bz2 –exclude .DS_Store my_files

# remove the copy
rm -r my_files
21 zzamboni // Jun 10, 2009 at 10:22 pm

Thank you – very nice, I had never noticed the -X option.
22 Ben // Jul 15, 2009 at 7:03 pm

I was unable to get the xattr stuff to remove the extended attributes from my Time Machine copies (I had done them originally with -p which was a bad idea, I suppose). However, using 'cp -rX' along with renames (and admin access) solved my problem.
23 zzamboni // Jul 16, 2009 at 8:16 am

I think this is because Time Machine files are also created with ACLs that disallow anyone from modifying them (they are meant to be permanent copies). I imagine any copies you make also get those ACLs copied. The easiest way around this is to temporarily disable ACLs on the file system using the fsaclctl command, or to use chmod to permanently remove the ACLs.
24 vikram jadhav // Aug 8, 2009 at 6:55 am

How to remove extended attribute from NTFS , using win32 API’s