How to print out content during the else condition?

That was in my edit2 section: else {die $response->status_line . ($response->content||'');}

Or, putting it into your whole script:

use strict;
use warnings;
use LWP::UserAgent();

my $ua = LWP::UserAgent->new(timeout => 10);
$ua->env_proxy;

my $response = $ua->get('https://www.sec.gov/Archives/edgar/full-index
+/2019/QTR1/master.idx');

open(OUT, ">" . "master") or die "Cannot open master";
    
if ($response->is_success) {print OUT $response->decoded_content; }
    else {die $response->status_line . ($response->content||'');}
    

close OUT;
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