String Modifiers
String Modifiers
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Finally, pattern matching can be used to modify strings of text. One of
the most common methods of modification is substitution. Substitution is
performed using the format
s/[pattern_to_find]/[pattern_to_replace_with]/
Thus, for example, the line:
s/eric/selena/
would change the line
eric is my name
to
selena is my name
The substitution function is modified most commonly with the /i and the
/g arguments. The /i argument specifies that matching should be done with
case insensitivity and the /g specifies that the match should occur globally
for the entire string of text rather than just for the first occurrence.
Thus, the line
s/eric/selena/gi
would change the line:
I am Eric, eric I am
to
I am selena, selena I am
without the /i, you would get
I am Eric, selena I am
and without /g but with the /i, you would get
I am selena, eric I am
There are many, many different kinds of matching
operators, anchors, and string modifiers.
If you want a more detailed explanation I recommend that you find a good
reference source on Regular Expressions. Otherwise, the above discussion
should explain how operators and anchors are commonly used in CGI
applications.
Additional Resources:
 Anchors
Table of Contents
The =~ operator
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