Drush was installed using PEAR. Drush by default was installed in /usr/share/php/drush folder. I am trying to run drush from my site root. Could someone please help to resolve this error? root@devdrupal:/var/www/drupal# drush pml Command pm-list needs a higher bootstrap level to run - you will need to [error] invoke drush from a more functional Drupal environment to run this command. The drush command 'pml' could not be executed. [error] [error] Drush was attempting to connect to: Drupal version : 7.23 Site URI : http://default Database driver : mysql Database username : drupaluser Database name : acquia_drupal Default theme : garland Administration theme : garland PHP executable : /usr/bin/php PHP configuration : /etc/php5/cli/php.ini PHP OS : Linux Drush version : 6.2.0 Drush configuration : Drush alias files : Drupal root : /var/www/drupal Site path : sites/default File directory path : sites/default/files