Unattended sign and encrypt a file using a script

[dtt]

A newbie question:
My bank asked me to upload a file signed and encrypted.
When I do
gpg --armor --sign -r <user> -o <file.gpg> -e <file.txt>
it always ask for a passphrase.
Since I am going to upload this file daily, how can I do the
signing unattendedly thru a script ?
I created a signature file mysignature.sig using gpg
--detach-sign, how can I use it in the signing process
without gpg prompting me to enter a passphrase ?
Thanks
David T