Drush to return all the local aliases for drush. Used for multisite installations.

multisite_aliases.drush.inc

<?php
/**
 * Get Local Alaises.
 *
 * Returns an array that is indexed by it's alias ID without that '@'.
 *
 * @return array Returns an array of local sites in the Drush site aliases.
 */
function _multisite_get_local_alias($group = NULL) {

  $alias = array();
  $result = (array) _drush_sitealias_find_and_load_all_aliases();

  if (empty($group) == TRUE) {

    foreach ($result as $id => $site) {

      if (empty($site['root']) == FALSE) {
        $alias[$site['#name']] = $site;
      }
    }
  } else {

    foreach ($results as $id => $site) {

      $current_group = substr($id, 0, strpos($id, '.'));

      if ($group == $current_group) {
        $alias[$sites['#name']] = $site;
      }
    }
  }

  return $alias;
}