F.1 Regular expressions that can be used by default
This section describes the regular expressions that can be used by default in Windows. Under UNIX, the regular expressions provided by the OS are applied, so the syntax is different from that explained below. For details on the regular expressions that can be used under UNIX, see the syntax (regexp or regex).
- Organization of this subsection
(1) Ordinary characters
An ordinary character is one that matches itself when specified as the search target in a regular expression. The only characters not handled as ordinary characters are the linefeed character and special characters. Ordinary characters are case sensitive.
(2) Special characters
Special characters are the caret (^), dollar sign ($), period (.), asterisk (*), and backslash (\).
These special characters are explained below.
- ^
-
The caret (^) signifies the beginning characters (match the start). The caret is a special character only when used as the first character in a regular expression. When specified elsewhere, the caret is handled as an ordinary character.
When written as a special character, matches are found for lines beginning with the same character string that starts the line (that is, that comes after the caret).
- $
-
The dollar sign ($) signifies the last characters (match the end). The dollar sign is a special character only when used as the last character in a regular expression. When specified elsewhere, the dollar sign is handled as an ordinary character.
When written as a special character, matches are found for lines ending with the same character string that ends the line (that is, that comes before the dollar sign). When used with the caret, matches are found for the exact character string written between the caret and dollar sign.
- (period)
-
The period (.) signifies any single character other than a linefeed character.
When written as a special character, matches are found for any single character other than a linefeed character.
- *
-
The asterisk (*) signifies zero or more repetitions of the preceding regular expression.
- \
-
The backslash (\) removes the special meaning of the special characters (* . ^ $ \).
When a backslash is written in front of a special character, the special character is handled as an ordinary character. Preceding a lower-case character with a backslash will produce an error, with the following exceptions:
- \n
-
Linefeed code
- \t
-
Tab character