print "\nH1. Attempt to list files ";
foreach $file ( @{$ls1}, @{$ls2}, @{$ls3}, @{$ls4} )    { 
    print "\nH1. $file ";
}

##</code><code>##

my $ls = $sftp->ls('/home/foo')
        or die "unable to retrieve directory: ".$sftp->error;

print "$_->{filename}\n" for (@$ls);

##</code><code>##

$pat4 = $envment . "REQ_*.req.copied";
...
$ls4 = $sftp->ls('/', names_only => 1, wanted=>qr/$pat4/);