"\n" =~ /(?s:.)/ # Match (local 'single line' modifier)
"ab" =~ /^.$/ # No match (dot matches one character)
-
=head2 Backslashed sequences
Perl regular expressions contain many backslashed sequences that
\S Match a non-white space character.
\h Match a horizontal white space character.
\H Match a character that isn't horizontal white space.
+ \N Match a character that isn't newline.
\v Match a vertical white space character.
\V Match a character that isn't vertical white space.
\pP, \p{Prop} Match a character matching a Unicode property.
=head3 White space
-C<\s> matches any single character that is consider white space. In the
+C<\s> matches any single character that is considered white space. In the
ASCII range, C<\s> matches the horizontal tab (C<\t>), the new line
(C<\n>), the form feed (C<\f>), the carriage return (C<\r>), and the
space (the vertical tab, C<\cK> is not matched by C<\s>). The exact set
this includes the space and the tab characters. C<\H> will match any character
that is not considered horizontal white space.
+C<\N>, like the dot, will match any character that is not a newline. The
+difference is that C<\N> will not be influenced by the single line C</s>
+regular expression modifier. (Note that, since C<\N{}> is also used for
+Unicode named characters, if C<\N> is followed by an opening brace and
+by a letter, perl will assume that a Unicode character name is coming.)
+
C<\v> will match any character that is considered vertical white space;
this includes the carriage return and line feed characters (newline).
C<\V> will match any character that is not considered vertical white space.