Question regarding unusual permissions in Mac OS X

By nicofournier at Mon, Apr 12 2010 10:07pm |

Dear all,

Not a subject for research but something I don't seem to be able to find information about.

Does anyone know what the @ means in the permissions when running, for instance, a ls -l in the terminal?

e.g., output from ls -l within a specific directory:

drwxr-xr-x@ 5 nicof staff 170 28 Aug 2009 perlmod
-rwxr-xr-x@ 1 nicof staff 14909 3 May 2009 postinstall.pl.in
-rw-r--r-- 1 nicof staff 4572 6 Apr 2009 readme.en.html
-rw-r--r--@ 1 nicof staff 4934 6 Apr 2009 readme.es.html
-rw-r--r--@ 1 nicof staff 5452 6 Apr 2009 readme.fr.html

Some the "Others" permissions have a @ at the very end. Nothing that I've done so far (chmod, etc) seems to have an effect on it (although it changes all the other permissions, including the "Others", adequately). I can't find any logic behind it. It's on executable shell scripts, directories, some I created, some I didn't, etc. This @ appears pretty much all across the file system and I'm looking for an answer that will reassure my IT management (it's hopefully NOT a threat, etc). Note that other Mac OS X users I've talked to have @'s in some of their permissions. Also, the @ does not seem to affect the behaviour of the file (e.g., executable, etc). Finally, when copying any file on a linux system, the @ doesn't appear anymore.

Apologies in advance if this is totally obvious, and any info would be much appreciated!

Regards,

Nico

-------------------------------------------------
Nicolas Fournier, Volcano Geodesist
GNS Science - Te Pu Ao - Wairakei Research Centre
Taupo, New Zealand
Web: www.gns.cri.nz - www.geonet.org.nz - www.volcanoloco.org

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Tue, 2010-04-13 04:12 — steja

Those are files with

Those are files with extended attributes.

From "man ls":
If the file or directory has extended attributes, the permissions field printed by the -l option is followed by a '@' character.

You can use "ls -@" to list the extended attributes, and "xattr" to print and set them.

Tue, 2010-04-13 06:06 — nicofournier

Thanks a bunch steja. It all

Thanks a bunch steja.

It all makes sense now. So long for my Unix brain to keep thinking that I don't need to look at "trivial" man pages!
Thanks again for the pointer.

Cheers

Nico

www.volcanoloco.org
www.gns.cri.nz