wild card

wild card

1. See wild (sense 4)

2. Computing a symbol that can represent any character or group of characters, as in a filename

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

wild card

[′wīld ‚kärd]

(computer science)

A symbolic character in a search argument such that any character will satisfy it.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

wild card

(operating system, programming, text)

(From card games in which certain cards, often the joker, can act as any other card) A special character or character sequence which matches any character in a string comparison, like ellipsis ("...") in ordinary written text.

In Unix filenames '?' matches any single character and '*' matches any zero or more characters. In regular expressions, '.' matches any one character and "[...]" matches any one of the enclosed characters.

See also Backus-Naur Form.

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

wild cards

Symbols used to represent any value when selecting specific files. In DOS, Windows and Unix, the asterisk (*) represents any collection of characters, and the question mark (?) represents a single character. In SQL, the percent sign (%) and underscore (_) are used for matching text. Note the following examples:

DOS and Windows (case insensitive)

 *.gif    .gif or .GIF extension

 a*.gif   beginning with "a" or "A"

 boot.*   all files named "BooT"
           any mix upper/lower case

 *.d*     extensions starting with
           "d" or "D"

 ?abc     1ABC, 2abc, etc.

 ??abc    10ABC, xxabc, etc.


 Windows only (case insensitive)

 *t.jpg   JPEG files ending with "T"


 Unix only (case sensitive)

 *.jpg    .jpg extension

 *.JPG    .JPG extension

 a*.jpg   beginning with "a"

 A*.jpg   beginning with "A"

 boot.*   all files named "boot"

 BOOT.*   all files named "BOOT"

 ?abc     1abc, xabc, etc.

 ??ABC    10ABC, XXABC, etc.


 SQL

 Good%    begining with "Good"

 _bcd     any name followed by "bcd"

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wildcard mask

A coding system used with access control lists to identify IP addresses. A line entry in the list contains a command, an IP address and a mask that references the IP address. Although access list commands are cryptic, an English translation of a line entry might be "deny entry to packets with these addresses."

The mask is a binary pattern that contains the same number of bits as the IP address. Each 0 bit in the mask means that the corresponding bit in the IP address must match exactly. A 1 indicates that the bit does not have to match and can be ignored. For example, in order to stipulate a specific IP address, that address would be accompanied by a wildcard mask of 0.0.0.0. To refer to all packets with Class A addresses in the 10.10.x.x range, the wildcard mask would be 0.0.255.255.

The Opposite of the Subnet Mask
Whereas a 0 bit in a wildcard mask means "match the bits," a 0 in a subnet mask means "do not match." Thus, a wildcard mask of 0.0.0.255 is the equivalent of a subnet mask of 255.255.255.0. See access control list, subnet mask and IP address. See also wild cards.

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