Assuming you are using strict and warnings,
Use quotemeta or \Q\E[0] instead of trying to escape things manually... Your
sanity will thank you.
And yes, the \D* could be troublesome; it depends on the text you are
matching against! For instance, 1.2.3.4.5 is not a valid IP, but you'd match
and replace part of it anyway. There's a great section about this on
Mastering Regular Expressions[1], "5.2.2. Matching an IP Address" and
"5.2.2.1. Know your context".
my $old_ip_address = "1.2.3.4";
my $new_ip_address = "5.6.7.8"
$read_line =~ s/
(?<![\w.]) #No alphanumeric or
period before the IP
\Q$old_ip_address_regexp\E #Quotemeta instead of trying to do
things by hand
(?![\w.]) #No alphanumeric or
period after the IP
/$new_ip_address/xg; #No need for $1 and $2, as we don't capture
anything.
Brian.
[0] http://perldoc.perl.org/functions/quotemeta.html
[1] http://regex.info/
