Is there a way to force "Yes" to any prompts when installing from apt-get (from a bash script)?

From the OPTIONS section of man apt-get

-y, --yes, --assume-yes
    Automatic yes to prompts; assume "yes" as answer to all prompts and
    run non-interactively. If an undesirable situation, such as
    changing a held package, trying to install a unauthenticated
    package or removing an essential package occurs then apt-get will
    abort. Configuration Item: APT::Get::Assume-Yes.

There is a unix command called

yes

Without options it outputs the string "y" repeatedly until killed.

To use it, simply pipe the result to the command where you need the confirmations:

yes | apt-get install ...

Read more in the Unix man pages or in the SO post The “yes” command.