I do not want to run something like
gpg -c as it prompts me for a passphrase. I will have cron job that backs-up and encypts some files. I want to pass in a location to a private key (via arguements) to an application that can encrypt a stream (ie: instead of encrypting just a file, it can use the pipe character,
|, as input).
Symmetric encryption like AES or the like is preferred.
One more thing, I want it to be a private key that I store somewhere on the file system. Not a private key that is managed by a key server or some kind of application specific key container.