Re: Regexp: Match anything except a certain word

[TedPride]

The following seems to work:

$_ = join '', <DATA>;
s/(<a href="https?:\/\/(?:(?!target=).)*?)>/$1 target="_blank">/igs;
print;

__DATA__
<a href="dsfsdf">sdfdsf</a>
<a href="http://dsfsdf">sdfdsf</a>
<a href="https://dsfsdf">sdfdsf</a>
<a href="http://dsfsdf" target="_blank">sdfdsf</a>
<a href="http://dsfsdf"
>sdfdsf</a>

[ikegami]

You're assuming the target will come after the href, but the OP allowed for any order.

See my earlier post for the fix.