Scheduled Maintenance: We are aware of an issue with Google, AOL, and Yahoo services as email providers which are blocking new registrations. We are trying to fix the issue and we have several internal and external support tickets in process to resolve the issue. Please see: viewtopic.php?t=158230
Debian 8.2 Jessie I have.
I want to add interactive step during Debian boot process.
To do this, added short script into /etc/rc.local to call read command.
I'm still getting my head around systemd myself TBH, but your problem is most likely that units/scripts are run asynchronously - it won't wait for your script unless you tell it to, and rc.local fires last anyway.
You'll most likely need to write a systemd .service file to run your script, and make it a dependency of the target you want to wait for it. e.g. 'WantedBy=multi-user.target'
Maybe something like this example.
Again, not a systemd guru, and that example is untested by me... but from what I understand it's the approach you'll need.
Once is happenstance. Twice is coincidence. Three times is enemy action. Four times is Official GNOME Policy.