Wildcard character

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Categories: Articles to be merged since March 2008 | Computer file formats | Pattern matching

For other meanings of 'wild card' see wild card.

The term wildcard character has the following meanings:

1 Telecommunication
2 Computing
3 References
4 See also
5 External links

Telecommunication

In telecommunications, a wildcard character is a character that may be substituted for any of a defined subset of all possible characters.

In high-frequency (HF) radio automatic link establishment, the wildcard character "?" may be substituted for any one of the 36 characters, "A" through "Z" and "0" through "9."
Whether the wildcard character represents a single character or a string of characters must be specified.

Computing

It has been suggested that this article or section be merged with glob (programming). (Discuss)

In computer (software) technology, a wildcard character can be used to substitute for any other character or characters in a string.

The asterisk (*) usually substitutes as a wildcard character for any zero or more characters, and the question mark (?) usually substitutes as a wildcard character for any one character, as in the CP/M, DOS, Microsoft Windows and POSIX (Unix) shells. (In Unix this is referred to as glob expansion.) In SQL, wildcard characters can be used in "LIKE" expressions; the percent sign (%) matches zero or more characters, and underscore (_) a single character. In Microsoft Access, wildcard characters can be used in "LIKE" expressions; the asterisk sign (*) matches zero or more characters, and question mark (?) a single character. In many regular expression implementations, the period (.) is the wildcard character for a single character.