usr File in Macintosh HD?

[pcs are junk]

Hi guys, I know that some base unix files are hidden inside Macintosh HD, and I know that sometimes they get unhidden, well, this happened to me with the private folder, and I deleted it, lol, then restored from a backup and found a command to get rid of it. but now another hidden file has become unhidden, the usr file, now I don't know what it is so I'm not gonna mess with it, but can some one please tell me the command to hide it, or give me a link to an article? thanks in advance!

 

[seepel]

voilà!
http://discussions.apple.com/thread.jspa?threadID=1662312

 

[pcs are junk]

thanks it worked!