[Attribute] System immutable [chflags flag] schg, schange, simmutable [Owner-settable] No [OS support] All [Semantics and rationale] File cannot be changed, renamed, moved, or removed [ls flag] 
schg
a r c h
o p a q u e
n o d u m p
s a p p n d
s c h g
u a p p n d
u c h g
h i d d e n