Do case-insensitive pattern matching.
+If C<use locale> is in effect, the case map is taken from the current
+locale. See L<perllocale>.
+
=item m
Treat string as multiple lines. That is, change "^" and "$" from matching
newline within the string, and "$" will match before any newline. At the
cost of a little more overhead, you can do this by using the /m modifier
on the pattern match operator. (Older programs did this by setting C<$*>,
-but this practice is deprecated in Perl 5.)
+but this practice is now deprecated.)
To facilitate multi-line substitutions, the "." character never matches a
newline unless you use the C</s> modifier, which in effect tells Perl to pretend
\E end case modification (think vi)
\Q quote regexp metacharacters till \E
+If C<use locale> is in effect, the case map used by C<\l>, C<\L>, C<\u>
+and <\U> is taken from the current locale. See L<perllocale>.
+
In addition, Perl defines the following:
\w Match a "word" character (alphanumeric plus "_")
\D Match a non-digit character
Note that C<\w> matches a single alphanumeric character, not a whole
-word. To match a word you'd need to say C<\w+>. You may use C<\w>,
-C<\W>, C<\s>, C<\S>, C<\d> and C<\D> within character classes (though not
-as either end of a range).
+word. To match a word you'd need to say C<\w+>. If C<use locale> is in
+effect, the list of alphabetic characters generated by C<\w> is taken
+from the current locale. See L<perllocale>. You may use C<\w>, C<\W>,
+C<\s>, C<\S>, C<\d>, and C<\D> within character classes (though not as
+either end of a range).
Perl defines the following zero-width assertions:
just like "^" and "$" except that they won't match multiple times when the
C</m> modifier is used, while "^" and "$" will match at every internal line
boundary. To match the actual end of the string, not ignoring newline,
-you can use C<\Z(?!\n)>.
+you can use C<\Z(?!\n)>. The C<\G> assertion can be used to mix global
+matches (using C<m//g>) and non-global ones, as described in
+L<perlop/"Regexp Quote-Like Operators">.
+It is also useful when writing C<lex>-like scanners, when you have several
+regexps which you want to match against consequent substrings of your
+string, see the previous reference.
+The actual location where C<\G> will match can also be influenced
+by using C<pos()> as an lvalue. See L<perlfunc/pos>.
When the bracketing construct C<( ... )> is used, \E<lt>digitE<gt> matches the
digit'th substring. Outside of the pattern, always use "$" instead of "\"
/$unquoted\Q$quoted\E$unquoted/
-Perl 5 defines a consistent extension syntax for regular expressions.
-The syntax is a pair of parentheses with a question mark as the first thing
-within the parentheses (this was a syntax error in Perl 4). The character
-after the question mark gives the function of the extension. Several
-extensions are already supported:
+Perl defines a consistent extension syntax for regular expressions.
+The syntax is a pair of parentheses with a question mark as the first
+thing within the parentheses (this was a syntax error in older
+versions of Perl). The character after the question mark gives the
+function of the extension. Several extensions are already supported:
=over 10
This is grandfathered for the RHS of a substitute to avoid shocking the
B<sed> addicts, but it's a dirty habit to get into. That's because in
-PerlThink, the right-hand side of a C<s///> is a double-quoted string. C<\1> in
+PerlThink, the righthand side of a C<s///> is a double-quoted string. C<\1> in
the usual double-quoted string means a control-A. The customary Unix
meaning of C<\1> is kludged in for C<s///>. However, if you get into the habit
of doing that, you get yourself into trouble if you then add an C</e>
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