Regular Expression Syntax
Use Basic Regular Expression (BRE) syntax for settings that take regular expressions. This syntax is summarized in the following table.
Metacharacter

Meaning

.

Matches any single character.

[ ]

Indicates a character class. Matches any character inside the brackets (for example, [abc] matches "a", "b", and "c").

^

If this metacharacter occurs at the start of a character class, it negates the character class. A negated character class matches any character except those inside the brackets (for example, [^abc] matches all characters except "a", "b", and "c").


If ^ is at the beginning of the regular expression, it matches the beginning of the input (for example, ^[abc] will only match input that begins with"a", "b", or "c").



In a character class, indicates a range of characters (for example, [09] matches any of the digits "0" through "9").

?

Indicates that the preceding expression is optional: it matches once or not at all (for example, [09][09]? matches "2" and "12").

+

Indicates that the preceding expression matches one or more times (for example, [09]+ matches "1", "13", "456", and so on).

*

Indicates that the preceding expression matches zero or more times.

??, +?, *?

Nongreedy versions of ?, +, and *. These match as little as possible, unlike the greedy versions that match as much as possible (for example, given the input "<abc><def>", <.*?> matches "<abc>" while <.*> matches "<abc><def>").

( )

Grouping operator. Example: (\d+,)*\d+ matches a list of numbers separated by commas (for example, "1" or "1,23,456").

\

Escape character: interpret the next character literally (for example, [09]+ matches one or more digits, but [09]\+ matches a digit followed by a plus character). Also used for abbreviations (such as \a for any alphanumeric character; see the following table).
If \ is followed by a number n, it matches the nth match group (starting from 0). Example: <{.*?}>.*?</\0> matches "<head>Contents</head>".

$

At the end of a regular expression, this character matches the end of the input (for example,[09]$ matches a digit at the end of the input).



Alternation operator: separates two expressions, exactly one of which matches (for example, Tthe matches "The" or "the").

!

Negation operator: the expression following ! does not match the input (for example, a!b matches "a" not followed by "b").

The following abbreviations are also supported.
Abbreviation

Matches

\a

Any alphanumeric character: ([azAZ09])

\b

White space (blank): ([ \\t])

\c

Any alphabetic character: ([azAZ])

\d

Any decimal digit: ([09])

\h

Any hexadecimal digit: ([09afAF])

\n

Newline: (\r(\r?\n))

\q

A quoted string: (\"[^\"]*\")(\'[^\']*\')

\w

A simple word: ([azAZ]+)

\z

An integer ([09]+)

