gistfile1

#!/usr/bin/env perl

use warnings;
use strict;

use Archive::Tar;

my $filename = $ARGV[0];
die "Specify filename as first argument.\n" unless $filename;

my $tar = Archive::Tar->new;
$tar->read($filename);

if ($tar->contains_file('./')) {
    $tar->remove('./');
    $tar->write($filename);
} else {
    warn "No root entry in $filename\n";
}