This example illustrates the difference between using the ^ (circumflex) character to match at the beginning of a line; along with using the circumflex inside square braces to negate a single character range.
This expression states not to match the uppercase alpha-character ranging from A thru S from the beginning of the line. As you you will notice: lines 1, 6, 13, 30, 31, 32, 33, 34, and 36 satisfies this match from the fortunes file.