#!/usr/bin/perl
use strict;
use warnings;
...
while (<$book>) {
	my $line = $_;
	my $plainline = $line;
	$plainline =~ s/["'.,!?:;\-()[\]{}|\\\/]/ /g; #replace all punctuation with a space
	my @sentence = split(/ /,$plainline);
	foreach my $word (@sentence) {
		chomp($word);
		my $whichword = 0;	# to track which badword was found
		foreach my $badword (@badwords) {
			if (lc($word) eq $badword) {
				my $newword = replaceword($whichword); #get a cleaner word to replace the naughty word
				$line =~ s/($word)/$newword/i;
			}
			$whichword++;
		}
	}
	$cleanbook .= $line;
}