RegEx Knife version 1.0.3 is available in the App Store. This version fixes a series of bugs (one quite serious) that escaped my notice when developing RegEx Knife 1.0.2.
It is emberassing to have these kinds of middle-of-the-road bugs remain in a product. This experience has reminded me why I need to recruit more testers for my iOS work, as I have always done for my Mac OS work. Going forward, RegEx Knife will have higher quality.