xattr is a Python wrapper for extended filesystem attributes.

xattr also ships with an xattr command line tool for viewing and 
editing extended filesystem attributes. On platforms that support or 
ship with the attr package, you may prefer to use the getfattr and 
setfattr command line tools from the attr package.

Extended attributes extend the basic attributes of files and 
directories in the file system. They are stored as name:data pairs 
associated with file system objects (files, directories, symlinks,
etc).

Extended attributes are currently only available on Darwin 8.0+ (Mac 
OS X 10.4) and Linux 2.6+. Experimental support is included for Solaris
and FreeBSD).