Related to that is getting rid of "file types". I remember at a "lessons of Unix" panel at a Usenix, that someone from the Labs gave an example of a situation where the operating system treated a file as more than just a set of bytes (think IBM, VMS, etc).  Read a source file (required them to do a bunch of file-conversion operations), write an output, perhaps changing a variable name from 'foo' to 'bar', and then compiling the output, which also required a bunch of file-conversion operations.