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.
