gistfile1.pl

#!/usr/bin/perl 

use strict;
use warnings;

# You'll likely need to `install` this.
# But don't worry, its just a text file.

use File::Find::Rule ();
use Path::Class qw( file  );
use File::Basename qw( basename );

my %unpacked = ();

while (1) {

  # Exclude anything thats already been unpacked from the unpack list
  my $exclude = File::Find::Rule->file->name( keys %unpacked );

  # Scan /downloads for files ending with .tar.gz that are not yet unpacked
  my @to_unpack =
    File::Find::Rule->file->name('*.tar.gz')->not($exclude)->in('/downloads');

  for (@to_unpack) {
    print "Found $_\n";
  }

  # If you find nothing, break the inifine while loop
  last if not(@to_unpack);

  # Unpack found items.
  for my $archive (@to_unpack) {

    # record the archive as unpacked in the hash-map
    $unpacked{$archive} = 1;

    my $file       = file($archive);
    my $parent_dir = $file->dir;

    # set this to 1 if you want to create a directory for each unpacked archive
    if (0) {

      # Create a directory named foo.tar.gz_unpacked
      $parent_dir = $parent_dir->subdir( basename($archive) . "_unpacked" );

      # Make sure it exists with mkdir
      $parent_dir->mkpath;
    }
    print "Extracting $file to $parent_dir \n";  
    # Could use Archive::Tar or something similar to do this
    # and this code would suddently become platform agnostic!
    system 'tar', '-C', $parent_dir, '-xf', $archive;
  }
}