GPG Command Line
GPG on the command line takes a huge number of possible switches and arguments. You only need to concern yourself with a handful of these:
-e or -d encrypts or decrypts, respectively
--gen-key creates a new key pair. You only need to use this the first time.
-u if you have more than one key pair this allows you to specify which to use when decrypting a message.
-r who the recipient of the message is if you are sending
--send-keys sends your public key to a keyserver so others can look you up and send you encrypted messages. Think of it like a phone book for PGP users.
--search-keys search by email address or name to see if your friend has a key on the keyserver
--recv-keys requests the public key for a particular user.
--keyserver lets you specify which keyserver to use for sending/recieving/searching
--sign-key validates that you are *sure* this key belongs to a particular user and is not a phony. Prevents error messages about unsigned keys, but is not otherwise required.
-a output ascii text for use in mail readers, web browsers, etc. You will almost always want to use this option as you can't copy/paste without it.
--export use this to send someone your public key directly without using a keyserver. You'll also want to add the -a to put it in ascii text the recipient can read, ie gpg -a --export
--import use this if your friend sends you her public key directly without using a keyserver
--verify use this to verify a signature
This is a pretty good walkthrough of the steps to take to set up GPG for a first time user:
A more detailed walkthrough is here: