Drupal 7 drush script to remove database prefix

fix_prefix.php

<?php

// current table prefix to be removed
$prefix = "drup_";
// echo generated statments rather then run them
$pretend = FALSE;

/////////////////////////////////////////////////////////////////////

$table_list = db_query("SHOW TABLES");
$prefix = strtolower($prefix);

foreach ($table_list as $r) {
  $r = (array)$r;
  $table_old = strtolower(current($r));

  // check for $prefix on this table
  if(substr($table_old,0,strlen($prefix)) == $prefix) {
    $table_new = substr($table_old, strlen($prefix));

    // first drop $table_new incase it already exists
    $clean_sql = "DROP TABLE IF EXISTS $table_new";
    // rename prefix table to standard/nonprefix name
    $rename_sql = "RENAME TABLE $table_old TO $table_new";

    if($pretend) {
      print $clean_sql."\n";
      print $rename_sql."\n";
    } else {
      if(!db_query($clean_sql)) {
        die("Aborting - $clean_sql \n");
      }
      if(!db_query($rename_sql)) {
        die("Aborting - $rename_sql \n");
      }
    }
  } else {
    print "$table_old skipped \n";
  }
}

print "\nDone \n\n";

?>