I am wondering what the characters \. mean in Perl, specifically in a matching expression. I know the \ can be an escape character. Is it simply escaping the dot? Or does it have an additional meaning together? 
In the context below, I am assuming that when the condition ($ARGV[$i] =~ /\./) is satisfied, the variable $Chain is not set to the argument $ARGV[$i]. I tried looking up information on Perl regular expressions and matching but I am having trouble fitting the context.
for (my $i = 0; $i <= $#ARGV; $i++) {
    if ($ARGV[$i] && ! ($ARGV[$i] =~ /\./)) {
        $Chain .= " " .  $ARGV[$i];
    }
}
 
     
    