pear channel-discover pear.drush.org Adding Channel "pear.drush.org" succeeded Discovery of channel "pear.drush.org" succeeded
and install:
pear install drush/drush downloading drush-6.2.0.0.tgz ... Starting to download drush-6.2.0.0.tgz (505,989 bytes) .....................................................................................................done: 505,989 bytes install ok: channel://pear.drush.org/drush-6.2.0.0
Docs:
http://docs.drush.org/en/master/usage/