Drush is a shell command line interface to a Drupal application. Since MediaMosa is based on Drupal, you can use any drush command on MediaMosa. Examples of such generic commands are;
drush cache-clear all
Cleares all caching tables;drush wd-show --tail
Shows the message log on the commandline
MediaMosa also has some specific drush commands supported for basic operations. For example;
drush mm-asset-list
Gives a list of assetsdrush mm-transcode <mediafile_id> <profile_id>
Starts a transcode job with profile id for a mediafile.
A full list of MediaMosa commands can be found when running drush without parameters.
MediaMosa drush does not have specific requirements for the drush version. A normal install will work. For example the debian drush package will work just fine. More installation instructions are found on the drush site: https://drupal.org/node/1791676
See also the drush faq: https://drupal.org/drush-faq