In a regular expression, using Scintilla's base implementation, special characters interpreted are:

.	Matches any character
\(	This marks the start of a region for tagging a match.
\)	This marks the end of a tagged region.
\n	Where n is 1 through 9 refers to the first through ninth tagged region when replacing. For example, if the search string was Fred\([1-9]\)XXX and the replace string was Sam\1YYY, when applied to Fred2XXX this would generate Sam2YYY. \0 refers to all of the matching text.
\<	This matches the start of a word using Scintilla's definitions of words.
\>	This matches the end of a word using Scintilla's definition of words.
\x	This allows you to use a character x that would otherwise have a special meaning. For example, \[ would be interpreted as [ and not as the start of a character set.
[...]	This indicates a set of characters, for example, [abc] means any of the characters a, b or c. You can also use ranges, for example [a-z] for any lower case character.
[^...]	The complement of the characters in the set. For example, [^A-Za-z] means any character except an alphabetic character.
^	This matches the start of a line (unless used inside a set, see above).
$	This matches the end of a line.
*	This matches 0 or more times. For example, Sa*m matches Sm, Sam, Saam, Saaam and so on.
+	This matches 1 or more times. For example, Sa+m matches Sam, Saam, Saaam and so on.

Regular expressions will only match ranges within a single line, never matching over multiple lines.
