\ 	Quote the next metacharacter
^	Match the beginning of the line
. 	Match any character (except newline)
$ 	Match the end of the line
| 	Alternation
()	Grouping
[]	Character class
*	Match 0 or more times
+	Match 1 or more times
?	Match 1 or 0 times
{n}	Match exactly n times
{n,}	Match at least n times
{n,m}	Match at least n but not more than m times
*? 	Match 0 or more times
+? 	Match 1 or more times
??	Match 0 or 1 time
{n}?	Match exactly n times
{n,}?	Match at least n times
{n,m}?	Match at least n but not more than m times
\t	tab
\n	newline
\r	return
\f	form feed
\v	vertical tab, whatever that is
\a	alarm (bell)
\e	escape
\033	octal char
\x1b	hex char
\c[ 	control char
\l	lowercase next char
\u	uppercase next char
\L	lowercase till \E
\U	uppercase till \E
\E	end case modification
\Q	quote regexp metacharacters till \E
\w	Match a "word" character (alphanumeric plus "_")
\W	Match a non-word character
\s	Match a whitespace character
\S	Match a non-whitespace character
\d	Match a digit character
\D	Match a non-digit character
\b	Match a word boundary
\B	Match a non-(word boundary)
\A	Match only at beginning of string
\Z	Match only at end of string
\G	Match only where previous m//g left off