Attributes for the <subst> Element

The <subst> element has the following attributes:

• match – A required attribute that is a case-sensitive Perl-like regular expression that is sought after in the input. This attribute can reference simple substitution variables.

• replace – A required attribute that is a Perl-like replacement value that is substituted for each occurrence of the pattern given by match. This value is not interpreted verbatim: the $n construct is interpreted as the nth parenthetical expression inside the matching expression. This attribute can reference simple substitution variables.

Example 2–5 Using the <subst> Element

The following transformation converts all occurrences of the string 127.0.0.xxx to 10.10.0.xxx in the /etc/hosts file:

<transform output=”/etc/hosts”>
    <subst match="127\.0\.0\.(\d+)"
    replace="10.10.0.$1"/>
</transform>