Sortix rw is a program that reads blocks from the standard input and copies them to the standard output until the end of the standard input. rw(1) is designed to be a replacement for dd(1), providing only the the core blockwise I/O. It has a standard command line interface with dashed options, useful and efficient defaults, and is simpler because it doesn't support converting the input (e.g. converting ASCII to/from EBCDIC).