GPG Usage tips
GnuPG (also called GPG) is a program that handles encryption, decryption and digital signatures. This page shows how to accomplish some typical operations, such as creating your initial key(-pair) and siging/encrypting documents.
The authoritative reference for this information is the [GNU Privacy Handbook].
Create a new key
Sign a document or file
There are multiple was to do this. I find the detached signature the most useful
gpg -b filename
this creates filename.sig.
To verify the signature (this proves the original filename was not tampered with)
gpg --verify filename.sig
Generate the key fingerprint