Possible Duplicate:
what does the @ mean on the output of ls on os x terminal?
I found this symbol @ when I run ls -al in my home folder, what does it mean here?
drwxr-xr-x 7 yangchenyun admin 238 Jul 19 16:32 Code
drwx------@ 25 yangchenyun admin 850 Oct 2 20:08 Dropbox
According to info ls, section 10.1.2, What information is listed (from the manual for GNU coreutils 8.5):
Following the file mode bits is a single character that specifies
whether an alternate access method such as an access control list
applies to the file. When the character following the file mode
bits is a space, there is no alternate access method. When it is
a printing character, then there is such a method.
So the @ indicates that there exists an alternate access method on the file. This most likely means an ACL. Try getfacl Dropbox and see what you get.
You may need to install some package to get the ACL-related commands. In Debian, getfacl is provided by the acl package, so sudo apt-get install acl if it isn't installed already. Other distributions may or may not use the same package name.
@ Seems to indicate extended attributes (at least in Mac OS X, see http://lists.apple.com/archives/darwin-userlevel/2007/Nov/msg00013.html)
lsmanpage has all the info, too.