USING: kernel io io.files io.streams.lines sequences ;

: drop/write ( outstream line -- outstream )
	dup "#" head?
	[ drop ]
	[ over stream-print ]
	if ;

: (remove-#-line) ( outstream -- outstream )
	[ readln dup ]
	[ drop/write ]
	[ drop ]
	while ;

: remove-#-line ( in-file out-file -- )
	<file-writer> swap <file-reader> <line-reader>
	[ (remove-#-line) stream-close ] with-stream ;