+Use of @samp{-O} is @emph{not} intended to mean simply ``use the name
+@var{file} instead of the one in the URL;'' rather, it is
+analogous to shell redirection:
+@samp{wget -O file http://foo} is intended to work like
+@samp{wget -O - http://foo > file}; @file{file} will be truncated
+immediately, and @emph{all} downloaded content will be written there.
+
+Note that a combination with @samp{-k} is only permitted when
+downloading a single document, and combination with any of @samp{-r},
+@samp{-p}, or @samp{-N} is not allowed.