Haystack is a powerful tool designed to enable each and every individual manage all of her information in the way that makes the most sense. By removing the arbitrary barriers created by applications that only handle certain information "types", and recording only a fixed set of relationships defined by the developer, users can define whichever arrangements of, connections between, and views of information they find most effective. Such personalization of information management will dramatically improve your ability to find what you need when you need it.
The xattr command lists, writes (sets), prints (displays), and deletes the extended attributes of file system objects. An extended attribute is a name:data (key:value) pairing arbitrarily associated with a file system object (e.g. file, directory, or symbolic link). The name of an extended attribute may be any null-terminated UTF-8 string. The data associated with it may be either textual or binary. This implementation of the xattr command is designed to be backwards-compatible with the Python script that shipped as /usr/bin/xattr in Mac OS 10.5.0 (Leopard).