Having just tried out a new piece of software which I couldn’t get to do the simple thing I needed (a filter based on blank lines – dead easy at the command line!) I decided to RTFM on its handling of regular expressions.
Here’s the part about the dollar character:
“A dollar character is an assertion which is true only if the current matching point is at the end of the subject string, or immediately before a newline character that is the last character in the string (by default). Dollar need not be the last character of the pattern if a number of alternatives are involved, but it should be the last item in any branch in which it appears. Dollar has no special meaning in a character class.”
I might have to name the author if that kind of thing continues.