Wouldn’t it be cool if once Reiser4 and other metadata-aware filesystem are more widespread you could have metadata-aware grep that allows you to search from the command line like you can from the iTunes search box, keying on any or all of the available data.
I don’t know about other filesystems, but Reiser4 should make this work automatically. The files can be navigated in the same way as directories, so a grep -r filename should also search metadata.
Well, it would be nice if Reiser didn’t kill your FS in the process though. Where I come from Reiser FS has a *very* bad reputation. Its personally hosed my machine twice — didn’t have the manners to even say good bye. The partitions literally disappeared.
This isn’t exactly the same thing, since it’s not filesystem metadata, but in OS X 10.4, the new metadata search thing “Spotlight” can be used from the command line.
What has been around my head for some time is what could be the next step in web search engines: they should be capables of metadata searches. Imagine this, I got this photo I don’t remember where I downloaded it, I want to contact the author but how? Then a metasearch would compare the binary data in the jpeg I have with the jpegs it has on its database and voila… I then now where this particular file is located.
It’s just a matter of time.
Check out Storage and Medusa for related efforts. Reiser4 is still very contentious, primarily due to its shaky SELinux and xattr support. It’s not yet in the mainline kernel. Regardless, GNOME and KDE aren’t going to rely on a specific filesystem for metadata. A middle layer such as Storage that will work with any filesystem will probably be the way. Storage will make use of a filesystem’s native metadata capabilies, if it has any, otherwise it will cook up its own metadata storage.