xargs, how to use

[Greg Strockbine]

I read in a book that you can use xargs to do the same thing
to a bunch of files one at a time.  So I tried it on my Ultrix
system using bash1.04, sh, and csh and they all barfed.  I even
consulted the man page but no go.  I tried something like this:
	ls -1 | xargs -i cp {} old.{}
basically all the shells complained about the {}.  So what gives,
how do you use this thing anyway.  What about repeat in the csh, 
how does that work?