Regular expressions

The following lists regular expression notation. Regular expressions can be used in queries and for field yanking in the file loader.

Characters

x              The character x

\\             The backslash character

\0n          The character with octal value 0n (0 <= n <= 7)

\0nn        The character with octal value 0nn (0 <= n <= 7)

\0mnn     The character with octal value 0mnn (0 <= m <= 3, 0 <= n <= 7)

\xhh         The character with hexadecimal value 0xhh

\uhhhh    The character with hexadecimal value 0xhhhh

\x{h...h}   The character with hexadecimal value 0xh...h

\t             The tab character ('\u0009')

\n            The newline (line feed) character ('\u000A')

\r             The carriage-return character ('\u000D')

\f             The form-feed character ('\u000C')

\a            The alert (bell) character ('\u0007')

\e            The escape character ('\u001B')

\cx           The control character corresponding to x

Character Classes

[abc]                        a, b, or c (simple class)

[^abc]                      Any character except a, b, or c (negation)

[a-zA-Z]                   a through z or A through Z, inclusive (range)

[a-d[m-p]]               a through d, or m through p: [a-dm-p] (union)

[a-z&&[def]]           d, e, or f (intersection)

[a-z&&[^bc]]           a through z, except for b and c: [ad-z] (subtraction)

[a-z&&[^m-p]]        a through z, and not m through p: [a-lq-z](subtraction)

Predefined Character Classes

.               Any character

\d            A digit: [0-9]

\D            A non-digit: [^0-9]

\s             A whitespace character: [ \t\n\x0B\f\r]

\S            A non-whitespace character: [^\s]

\w           A word character: [a-zA-Z_0-9]

\W           A non-word character: [^\w]

Boundary Matchers

^              The beginning of a field

$              The end of a field

\b            A word boundary

\B            A non-word boundary

Greedy quantifiers

X?            X, once or not at all

X*            X, zero or more times

X+            X, one or more times

X{n}         X, exactly n times

X{n,}        X, at least n times

X{n,m}     X, at least n but not more than m times

Reluctant quantifiers

X??          X, once or not at all

X*?          X, zero or more times

X+?          X, one or more times

X{n}?       X, exactly n times

X{n,}?      X, at least n times

X{n,m}?   X, at least n but not more than m times

Possessive quantifiers

X?+          X, once or not at all

X*+          X, zero or more times

X++          X, one or more times

X{n}+       X, exactly n times

X{n,}+      X, at least n times

X{n,m}+   X, at least n but not more than m times

Logical operators

XY            X followed by Y

X|Y          Either X or Y

(X)           X, as a capturing group

Quotation

\              Nothing, but quotes the following character

\Q            Nothing, but quotes all characters until \E

\E            Nothing, but ends quoting started by \Q