Using gpg

I am trying to use gig in linux but it is hanging.

$ gpg --passphrase=test /tmp/test.sh
Reading passphrase from file descriptor 0 ...

When i press enter, it gives the below message:

$ gpg --passphrase=test /tmp/test.sh
Reading passphrase from file descriptor 0 ...
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof


[applsuprt@rvbd-chi-spap01 tmp]$ gpg --batch --passphrase=test /tmp/test.sh

gpg: no valid OpenPGP data found.
gpg: processing message failed: eof

Could you please help.
We are using below linux:

Red Hat Enterprise Linux AS release 4 (Nahant Update 8)

What are you expecting to happen with this command? That /tmp/test.sh is encrypted?