Since regexes are often hard to negate (correct me if I'm wrong...), and I'm starting to think of making this more "grep compliant", how about this:

* Get rid of all the current "NOT" arguments, e.g. `-e`, `-c`.  Keep only the positive ones.
* Add an "invert search" option, `-v` (same as grep).
* Change upper case options to lower case.

Now we would have `-r` for regex search, `-e` for equals, `-c` for contains.  We could also add an `-i` for *case insensitive*.  Of course the equals/contains are redundant with common regular expressions, but have the  advantage of being less scary to beginners, and not requiring escaping of special characters.

What do you think?