I have a shell provisioning script that invokes a command that requires user input - but when I run vagrant provision, the process hangs at that point in the script, as the command is waiting for my input, but there is nowhere to give it. Is there any way around this - i.e. to force the script to run in some interactive mode?

The specifics are that I creating a clean Ubuntu VM, and then invoking the Heroku CLI to download a database backup (this is in my provisioning script):

curl -o /tmp/db.backup `heroku pgbackups:url -a myapp`

However, because this is a clean VM, and therefore this is the first time that I have run an Heroku CLI command, I am prompted for my login credentials. Because the script is being managed by Vagrant, there is no interactive shell attached, and so the script just hangs there.

Edit
Report