Supported Metacharacters

Apache supports the metacharacters and metasequences listed in Table 48 through Table 52. For expanded definitions of each metacharacter, see "Regex Metacharacters, Modes, and Constructs.”

Table 1-48. Apache character representations

Sequence

Meaning

\octal

Character specified by a three-digit octal code.

\xhex

Character specified by a one- or two-digit hexadecimal code.

\x{hex}

Character specified by any hexadecimal code.

\cchar

Named control character.

Table 1-49. Apache character classes and class-like constructs

Class

Meaning

[...]

A single character listed, or contained within a listed range.

[^...]

A single character not listed, and not contained within a listed range.

[:class:]

POSIX-style character class (valid only within a regex character class).

.

Any character, except newline (unless single-line mode, /s).

\C

One byte; however, this may corrupt a Unicode character stream.

\w

Word character, [a-zA-z0-9_].

\W

Nonword character, [^a-zA-z0-9_].

\d

Digit character, [0-9].

\D

Nondigit character, [^0-9].

\s

Whitespace character, [\n\r\f\t ].

\S

Nonwhitespace character, [^\n\r\f\t ].

Table 1-50. Apache anchors and zero-width tests

Sequence

Meaning

^

Start of string.

$

End of search string.

\b

Word boundary; position between a word character (\w) and a nonword character (\W), the start of the string, or the end of the string.

\B

Not-word-boundary.

(?=...)

Positive lookahead.

(?!...)

Negative lookahead.

(?<=...)

Positive lookbehind.

(?<!...)

Negative lookbehind.

Table 1-51. Apache comments and mode ...

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