[wplug-bsd] chflags(1)

[Brandon Kuczenski]

I recently observed that my FreeBSD system has a chflags(1) command which 
"modifies the file flags of the listed files," including, for example, 
whether writes to a file may only append, whether it is 'opaque wrt. 
union' (there's no manpage for union) and so on.  There's no similar 
command on my Linux system, and indeed it looks like chflags(2) is a 
system call that is specific to BSD (the man page says it first appeared 
in BSD 4.4 -- I love BSD..  It's a reference library as well as an 
operating system.)

So my question (which may be somewhat tenuously topical to the list) is, 
whether this animal seen much in the wild-- do people use this feature? 
What is it most useful for?  Is it endemic to the ufs filesystem, or 
general to the operating system?

-Brandon