Note that a combination with @samp{-k} is only permitted when
downloading a single document, as in that case it will just convert
all relative URIs to external ones; @samp{-k} makes no sense for
-multiple URIs when they're all being downloaded to a single file.
+multiple URIs when they're all being downloaded to a single file;
+@samp{-k} can be used only when the output is a regular file.
@cindex clobbering, file
@cindex downloading multiple times