gpg --encrypt --recipient 'user@emailaddress.com' example.txt
gpg --encrypt --recipient $USER example.txt

gpg --decrypt example.txt.gpg
gpg --output example.txt --decrypt example.txt.gpg

gpg --gen-key
gpg --full-generate-key

To list a summary of all keys

gpg --list-keys
gpg --list-secret-keys

To show your public key

gpg --armor --export

To show the fingerprint for a key

gpg --fingerprint KEY_ID

gpg --search-keys 'user@emailaddress.com'

gpg --output ~/public_key.txt --armor --export KEY_ID
gpg --output ~/private_key.txt --armor --export-secret-key KEY_ID

Retrieve the key files which you previously exported.

gpg --import ~/public_key.txt
gpg --allow-secret-key-import --import ~/private_key.txt

Then delete the private key file.

shred -zu ~/private_key.txt

Retrieve key ID then delete

gpg --list-secret-keys
gpg --list-keys
gpg --delete-keys ID
gpg --delete-secret-keys ID