Redmine

Hello folks,
I'm a very noob on redmine configuration and linux in general. I have a ready-to-use Ubuntu Bitnami stack which works well.
Now I need to add a script to my cron table to rake email from an imap mailbox; from terminal I'm able to run use_redmine, change into correct folder then run all the rake redmine:email:receive_imap command, and it works correctly.
Now I want to move this into a script that I want to add to cron to be scheduled regularly.
The problem is, if I add use_redmine in my .sh script it simply waits for user input without reading the following lines.

Anybody have an idea about how to solve this?

Thank you in advance,
Matteo