Feature | Syntax | Description | Example | .NET | Java | Perl | PCRE2 | PHP | Delphi | R | JavaScript | VBScript | XRegExp | Python | Ruby | std::regex | Boost | Tcl ARE | Oracle | XPath |
Backslash |
Backslash followed by any character that does not form a token |
A backslash that is followed by any character that does not form a replacement string token in combination with the backslash inserts the escaped character literally. |
Replacing with \! yields ! |
no | YES | YES | extended | no | no | YES | no | no | no | 3.7–3.10 error | no | sed | YES | no | no | error |
Backslash |
A backslash that does not form a token |
A backslash that is not part of a replacement string token is a literal backslash. |
Replacing with \! yields \! |
YES | no | no | default | YES | YES | no | YES | YES | YES | YES | YES | default | no | YES | YES | error |
Backslash |
Trailing backslash |
A backslash at the end of the replacement string is a literal backslash. |
Replacing with \ yields \ |
YES | error | error | default | YES | YES | no | YES | YES | YES | error | YES | default | YES | YES | YES | error |
Backslash |
\\ |
A backslash escapes itself. |
Replacing with \\ yields \ |
no | YES | YES | extended | YES | YES | YES | no | no | no | YES | YES | sed | YES | YES | YES | YES |
Dollar |
A dollar that does not form a token |
A dollar sign that does not form a replacement string token is a literal dollar sign. |
Replacing with $! yields $! |
YES | error | error | error | YES | YES | YES | YES | YES | error | YES | YES | YES | YES | YES | YES | error |
Dollar |
Trailing dollar |
A dollar sign at the end of the replacement string is a literal dollar sign. |
Replacing with $ yields $ |
YES | error | error | error | YES | YES | YES | YES | YES | 2–4 | YES | YES | default VC’15–VC’22 sed VC’08–VC’22 | YES | YES | YES | error |
Dollar |
$$ |
A dollar sign escapes itself. |
Replacing with $$ yields $ |
YES | error | error | YES | no | YES | no | YES | YES | YES | no | no | default | all default | no | no | error |
Dollar |
\$ |
A backslash escapes a dollar sign. |
Replacing with \$ yields $ |
no | YES | YES | extended | YES | YES | YES | no | no | no | 3.7–3.10 error | no | sed | YES | no | no | YES |
Hexadecimal escape |
\xFF where FF are 2 hexadecimal digits |
Inserts the character at the specified position in the code page |
\xA9 inserts © when using the Latin-1 code page |
no | no | YES | extended | string | no | string | string | no | string | string | string | string | YES | string | no | error |
Unicode escape |
\uFFFF where FFFF are 4 hexadecimal digits |
Inserts a specific Unicode code point. |
\u00E0 inserts à encoded as U+00E0 only. \u00A9 inserts © |
no | string | no | extended error | no | no | string | string | no | string | string | 1.9 string | string | no | string | no | error |
Unicode escape |
\u{FFFF} where FFFF are 1 to 4 hexadecimal digits |
Inserts a specific Unicode code point. |
\u{E0} inserts à encoded as U+00E0 only. \u{A9} inserts © |
no | no | no | extended error | 7.0.0 string | no | string | string | no | string | 3.7–3.10 error | 1.9 string | no | no | no | no | error |
Unicode escape |
\x{FFFF} where FFFF are 1 to 4 hexadecimal digits |
Inserts a specific Unicode code point. |
\x{E0} inserts à encoded as U+00E0 only. \x{A9} inserts © |
no | no | YES | extended | no | no | no | no | no | no | 3.7–3.10 error | no | no | YES | no | no | error |
Character escape |
\n , \r and \t |
Insert an LF character, CR character and a tab character respectively |
\r\n inserts a Windows CRLF line break |
no | string | YES | extended | string | no | string | string | no | string | YES | string | string | YES | string | no | error |
Character escape |
\a |
Insert the “alert” or “bell” control character (ASCII 0x07) |
|
no | no | YES | extended | no | no | no | no | no | no | YES | no | no | YES | no | no | error |
Character escape |
\b |
Insert the “backspace” control character (ASCII 0x08) |
|
no | no | YES | extended error | no | no | no | no | no | no | YES | no | no | no | no | no | error |
Character escape |
\e |
Insert the “escape” control character (ASCII 0x1B) |
|
no | no | YES | extended | no | no | no | no | no | no | 3.7–3.10 error | no | no | YES | no | no | error |
Character escape |
\f |
Insert the “form feed” control character (ASCII 0x0C) |
|
no | no | YES | extended | no | no | no | no | no | no | YES | no | no | YES | no | no | error |
Character escape |
\v |
Insert the “vertical tab” control character (ASCII 0x0B) |
|
no | no | no | extended error | no | no | no | no | no | no | YES | no | no | YES | no | no | error |
Control character escape |
\cA through \cZ |
Insert an ASCII character Control+A through Control+Z, equivalent to \x01 through \x1A |
\cM\cJ inserts a Windows CRLF line break |
no | no | YES | extended | no | no | no | no | no | no | no | no | no | YES | no | no | no |
Control character escape |
\ca through \cz |
Insert an ASCII character Control+A through Control+Z, equivalent to \x01 through \x1A |
\cm\cj inserts a Windows CRLF line break |
no | no | YES | extended | no | no | no | no | no | no | no | no | no | YES | no | no | no |
NULL escape |
\0 |
Insert the NULL character |
|
no | no | YES | extended error | no | no | no | no | no | no | YES | no | no | all default | no | no | error |
Octal escape |
\o{7777} where 7777 is any octal number |
Inserts the character at the specified position in the active code page |
\o{20254} inserts € when using Unicode |
no | no | 5.14 | extended | no | no | no | no | no | no | 3.7–3.10 error | no | no | no | no | no | error |
Octal escape |
\10 through \77 |
Inserts the character at the specified position in the ASCII table |
\77 inserts ? |
no | no | YES | extended error | no | no | no | no | no | no | no | no | no | no | no | no | error |
Octal escape |
\100 through \177 |
Inserts the character at the specified position in the ASCII table |
\100 inserts @ |
no | no | YES | extended error | no | no | no | no | no | no | YES | no | no | no | no | no | error |
Octal escape |
\200 through \377 |
Inserts the character at the specified position in the active code page |
\377 inserts ÿ when using the Latin-1 code page |
no | no | YES | extended error | no | no | no | no | no | no | YES | no | no | no | no | no | error |
Octal escape |
\400 through \777 |
Inserts the character at the specified position in the active code page |
\777 inserts ǿ when using Unicode |
no | no | YES | extended error | no | no | no | no | no | no | no | no | no | no | no | no | error |
Octal escape |
\01 through \07 |
Inserts the character at the specified position in the ASCII table |
\07 inserts the “bell” character |
no | no | YES | extended error | no | no | no | no | no | no | YES | no | no | all default | no | no | error |
Octal escape |
\010 through \077 |
Inserts the character at the specified position in the ASCII table |
\077 inserts ? |
no | no | YES | extended error | no | no | no | no | no | no | YES | no | no | all default | no | no | error |
Feature | Syntax | Description | Example | .NET | Java | Perl | PCRE2 | PHP | Delphi | R | JavaScript | VBScript | XRegExp | Python | Ruby | std::regex | Boost | Tcl ARE | Oracle | XPath |
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