Batch Mode and decrypt

[jane grove]

Hello,
I am trying to use the GnuPG command "decrypt" in batch mode (i.e. in a script).
When I use the option "--batch", I don't have a way to enter the user
id or passphrase.
In batch mode, the gpg command cannot be interactive.
I tried "gpg --batch --decrypt filename userid", but it didn't work.
In batch mode, how do I use the gpg command to decrypt a file with a userid?
Thanks.