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

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