.
Match any character except NULL, empty string, or newline: (e.g. (…) matches ‘eN2′, ‘774′, ‘Akc’, etc, but not ‘ ‘)
*
Match preceding character 0 or more times: (e.g. ab*c matches ‘ac’, ‘abc’, ‘abbbc’, etc)
+
Match preceding character 1 or more times: (e.g. [hc]+at matches ‘hat’, ‘cat’, ‘chat’, ‘hcat’, ‘ccchat’ but not ‘at’)
?
Match preceding character 0 or 1 time: (e.g. [hc]?at matches ‘hat’, ‘cat’, and ‘at’
[characters]
Match any characters within []: (e.g. [0-9a-zA-Z] matches all alphanumeric characters)
^(character class)
Match all characters except those in character class: (e.g. [^abc] matches all characters except ‘a’, ‘b’, or ‘c’)
-
Create range of characters: (e.g. [0-9a-zA-Z] matches all alphanumeric characters)
(pattern)
Search for a subpattern: (e.g. [(fools)(fool's)] gold matches “fools gold” or “fool’s gold”)
Escapes special character (e.g. . will treat a . as a literal period instead of parsing it’s special meaning)
^
Matches the starting position within the string
$
Matches the ending position of the string
{number}
Match number of instances of preceding character
{number,}
Match number or more instances of preceding character
{Number1,Number2}
Match between Number1 and Number2 instances of preceding characters (inclusive)
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