TL;DR: to pass arguments in file to bin/magento use the xargs -a command.
During a tech talk at Magento Imagine 2017 someone asked if it was possible to extend the bin/magento tool to get arguments from file.
Actually it isn’t necessary: *nix shells already give us the opportunity to pass a file containing command arguments through the xargs -a command.
For example, if we create an install.args file with the following content:
setup:install --admin-firstname="Admin" --admin-lastname="User" --admin-email="mageadmin@example.com" --admin-user="admin" --admin-password="password" --db-host="localhost" --db-name="magento" --db-user="magento" --db-password="password" --backend-frontname="admin"
we can install Magento 2 by executing the following command:
xargs -a install.args bin/magento
Quick and handy!
Photo credits: Tim Gouw - Creative Commons license