Drush 8 hangs with any command Up until recently, I've been using version 6 of drush, and it worked like a charm. Since I started delving into Drupal 8, I installed drush 7 on my Mac using the install instructions (using Composer) for global drush. Initially, it was fine, but whenever I try to run it now, it just hangs. When I run it with -d, it gets this far:

Using the Drush script found at /Users/steve/.composer/vendor/drush/drush/drush.launcher using pcntl_exec


Running which drush shows the correct path  (/Users/steve/.composer/vendor/bin/drush), but like I said, running drush by itself or with any other command, it just hangs. From what I understand, the only error logging is to the screen, but since there's nothing being displayed to the screen, I'm not sure where to look. I don't have memcache installed (unlike this guy), so I know that's not the problem. Any suggestions?

Thanks 

UPDATE: I am using Drush 8 not Drush 7 (I fixed the title accordingly). After a couple days, it's back to hanging again, and even using -d shows nothing.
Only Drush 8 is compatible with Drupal 8. See http://docs.drush.org/en/master/install/#drupal-compatibility