As far as I know you can't get users access token without users interaction.
You can get app token though like this:
facebook.get_app_access_token(APP_ID, APP_SECRET)
To get APP_ID and APP_SECRET you need to create new app here: https://developers.facebook.com/ Note that you will get much less meta data using app's token than using user's token.
I was writing script collecting data from facebook lately and I had same problem. I just switched to app token since my script runs every hour as cron job so it was impossible to deliver new token every time manually.