Grep is such an elegant linux tool, one that you might use from the command line in many different ways without even thinking about it. It’d be nice if non-plaintext file formats still worked with grep, e.g. pdf files.
While you can’t just grep pdf files as is, if you download a nice specialized tool called pdfgrep (http://pdfgrep.sourceforge.net/), then your command-line life might be much enriched. Perhaps down the road some extensible grep-like tool might exist that offers plugins for searching through other binary file formats (microsoft word, open office, etc.); or perhaps such a thing already exists and I’m merely ignorant of it?