User Input: She sells Seashells by the seashore.
Search Pattern: sea
Replacement Pattern: bay
Final Output: She sells bayshells by the bayshore.

But what I want it to do is keep the capitalization.
Final Output: She sells Bayshells by the bayshore.

##</code><code>##

main();

sub main {


print "Text to be analyzed.\n";
print "Type a blank line when finished.\n\n";

while (<>) {
        /^$/&& last;
        $input.=$_}

        chomp($input);

        replace ();

        $input = "";

        again ();
}

sub replace {

        print "\nSearched for: ";
        $pattern = <>;
        chomp($pattern);

        print "\nReplace with: ";
        $replacement = <>;
        chomp($replacement);

        $input =~ s/$pattern/$replacement/ig;
}