title: heroku error bash: gunicorn: command not found
body: <p>I pushed my Flask app to Heroku couple months ago <a href="https://shakespeare-tweet.herokuapp.com/" rel="nofollow noreferrer">https://shakespeare-tweet.herokuapp.com/</a> (live)
  here's the screen shot of the local host: <a href="https://berkeley.app.box.com/file/303628505050" rel="nofollow noreferrer">https://berkeley.app.box.com/file/303628505050</a>
  But I tried to update it, and it keeps breaking: </p>
  
  <p>Here's stackoverflow solution: <a href="https://stackoverflow.com/questions/33021874/heroku-gunicorn-not-working-bash-gunicorn-command-not-found">Heroku + gunicorn not working (bash: gunicorn: command not found )</a></p>
  
  <p>but when I update it to the new version, it gives me the error 
  Heroku + gunicorn not working (bash: gunicorn: command not found )</p>
  
  <p>web: gunicorn myapp:app --log-file=-
  But the app crashes when deployed:</p>
  
  <p>bash: gunicorn: command not found 
  I tried adding the heroku python buildpack, but no luck. If I roll back to a previous commit (where requirements.txt and Procile are both unchanged).</p>
  
  <p>I still get the same error log:</p>
  
  <pre><code>2018-07-10T21:52:11.855058+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=shakespeare-tweet-pr-16.herokuapp.com request_id=068bae51-052e-4bf4-9b25-336c9a036709 fwd="165.124.160.252" dyno= connect= service= status=503 bytes= protocol=https
  2018-07-10T21:52:31.144603+00:00 heroku[web.1]: State changed from crashed to starting
  2018-07-10T21:52:34.984576+00:00 heroku[web.1]: Starting process with command `gunicorn app:app`
  2018-07-10T21:52:36.771041+00:00 heroku[web.1]: Process exited with status 127
  2018-07-10T21:52:36.714985+00:00 app[web.1]: bash: gunicorn: command not found
  2018-07-10T21:52:36.787124+00:00 heroku[web.1]: State changed from starting to crashed
  2018-07-10T21:52:36.789041+00:00 heroku[web.1]: State changed from crashed to starting
  2018-07-10T21:52:40.971471+00:00 heroku[web.1]: Starting process with command `gunicorn app:app`
  2018-07-10T21:52:42.677787+00:00 heroku[web.1]: Process exited with status 127
  2018-07-10T21:52:42.692987+00:00 heroku[web.1]: State changed from starting to crashed
  2018-07-10T21:52:42.618587+00:00 app[web.1]: bash: gunicorn: command not found
  Disconnected from log stream. There may be events happening that you do not see here! Attempting to reconnect...
  Connection to log stream failed. Please try again later.
  
  I would appreciate any help with this issue.
  </code></pre>