#!/usr/bin/perl 
use strict;
use warnings;
use Data::Dumper;

my @arr;

while (<DATA>){
    chomp;
    push @arr, $_ if s/ \s+ ( [\/]{2} .+ ) /$1/xms;
}

print Dumper \@arr;

__DATA__
  //opiopiopi
  -//popoiop
  uytyu
  ---
 //llmùlùm
  //fghfghf
-//sdsdfsdfs
[download]

Output :

$VAR1 = [
          '//opiopiopi',
          '//llmùlùm',
          '//fghfghf'
        ];
[download]

hth,

PooLpi