OS X flags for further controlling what can be done with folders and files.
http://www.macosxhints.com/article.php?story=20031017061722471
arch - "archived flag"
opaque - "opaque flag"
nodump - "nodump flag"
sappnd - "system append-only flag"
schg - "system immutable flag"
uappnd - "user append-only flag"
uchg - "user immutable flag"
Lock a file from being moved, renamed or deleted:
chflags uchg filename
Undo it with:
chflags nouchg filename
