Regular expression syntax

.

Matches any character; used as a wildcard when creating a search string.

***

Matches zero or more instances of the previous pattern item.

+

Matches one or more instances of the previous pattern item.

?

Matches zero or one instances of the previous pattern item.

( )

Groups subpattern; repetition and alternation operators apply to the entire preceding subpattern.

|

Allows for alternation of a pattern.

For example, to match Hello or hello in a string, the regular expression should read: Hello|hello.

[ ]

Delimits a set of characters; the range is specified as [x-y].

If the first character in the set is ^, there is a match only when the remaining characters in the set are not present.

^

Anchors the pattern to the beginning of the string; this character must be the first character in the set.

$

Anchors the pattern to the end of the string; this character must be the last character in the set.