So, I decided to learn some Perl earlier today. I had a small script that downloaded and converted a hosts file for use with unbound:

 
#!/bin/sh
curl https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts 
+|grep '^0\.0\.0\.0' | awk '{print "local-zone: \""$2"\" redirect\nloc
+al-data: \""$2" A 0.0.0.0\""}' > ads.conf
[download]

Which discards all lines except lines like this:

0.0.0.0 apps.id.net

And changes it into two lines like this:

local-zone: "apps.id.net" redirect
local-data: "apps.id.net A 0.0.0.0"
[download]

I poked around this site and read some docs and came up with this:

#!/usr/bin/perl
use strict;
use warnings;
use LWP::Simple;

my $url = "https://raw.githubusercontent.com/StevenBlack/hosts/master/
+hosts";
open(my $file, '>', 'ads.conf') or die "wtfile?";
for (split /^/, get ($url)) {
        if ($_ =~ /0\.0\.0\.0/ and $_ !~ /#/){
                $_ =~ s/0\.0\.0\.0 //;
                $_ =~ s/\n//;
                print $file "local-zone: \"" . $_ . "\" redirect\nloca
+l-data: \"" . $_ . " A 0.0.0.0\"\n";
        }
}
close $file;
[download]

Turns out the Perl script takes 5 times as long as the shell script, and uses nearly twice the cpu. What mistakes did I make, and is there a way to do this in Perl faster then the shell script can?

Updated script based on comments:

#!/usr/bin/perl
use strict;
use warnings;
use LWP::Simple;

my $url = "https://raw.githubusercontent.com/StevenBlack/hosts/master/
+hosts";
open(my $file, '>', 'ads.conf') or die "wtfile?";
for (split /^/, get ($url)) {
        if ($_ =~ /^\Q0.0.0.0\E (.*)$/){
                print $file "local-zone: \"" . $1 . "\" redirect\nloca
+l-data: \"" . $1 . " A 0.0.0.0\"\n";  
        }
[download]

Update 2, thank you marioroy (link) and rizzo (link), combining your two suggestions gets me the fastest script so far:

#!/usr/bin/perl
use strict;
use warnings;

my $_url = "https://raw.githubusercontent.com/StevenBlack/hosts/master
+/hosts";
open(my $file, '>', 'ads.conf') or die "wtfile?";

my $var = `curl $_url` or die "wturl?";

while($var =~ /(\n0\.0\.0\.0)(\s)([\w\.]+?)\s+/g){
        print $file "local-zone: \"" . $3 . "\" redirect\nlocal-data: 
+\"" . $3 . " A 0.0.0.0\"\n";
}
close $file;
[download]

Interestingly that script, seems to be on par with the shell script time wise, but does it using 1/6th the cpu.

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