B.7 Substitutions

Substitutions are allowed only within find/replace replacement patterns.

Character escapes and substitutions are the only special constructs recognized in a replacement pattern.

The following table shows how to define named and numbered replacement patterns:

Table B.8

List of Substitutions

Character

Description

$1

Substitutes the last substring matched by group number 1 (decimal). The second group is number 2 ($2), and so on.

For example, the replacement pattern a*$1b inserts the string a* followed by the substring matched by the first capturing group, if any, followed by the string b.

$0

Substitutes a copy of the entire match itself.

$&

Substitutes a copy of the entire match itself.

$$

Substitutes a single $ literal.

Remark 1.

The * character is not recognized as a metacharacter within a replacement pattern.

Remark 2.

$ patterns are not recognized within regular expression matching patterns. Within regular expressions, $ designates the end of the string.