while (<DATA>) {
        my @urls = ( $_ =~ /(https?\:\/\/.*?\.foo\.com)/g);
        foreach my $url (@urls) {

        print "$url\n" if $1;
    }

}

__DATA__
http://www.foo.com/fishnuts
http://smtp.foo.com https://www.foo.com/?(bunch-of-stuff):{}https://svn.foo.com/docs
https://yahoo.de/?search:{width}-https://www.foo.com
https://google.com https://foo.com:(More-random-stuff)https://yahoo.de::http://pubdocs.foo.com/top/index.html

##</code><code>##

http://www.foo.com
http://smtp.foo.com
https://www.foo.com
https://svn.foo.com
https://www.foo.com
https://foo.com
http://pubdocs.foo.com

##</code><code>##

/(https?\:\/\/(?!http.)*?\.foo\.com)/g