drush features-clone <src_featurename> <dst_featurname>
src_featurename - Required. Modulename (machine name) of the Feature to Clone.
dst_featurename - Required. Machine name of the new Feature created after cloning.
Note: source feature must be installed and enabled on a Drupal instance that the drush command is run against.
Module uses pretty straightforward search/replace technique so if the name of your feature is something non-unique and can match some other things in your codebase, unintended/unpleasant consequences may follow. Please name your features with unique names and as with any other change to codebase: backup, test, test again.
Please refer to the included INSTALL.txt for detailed installation instructions.