$ curl cheat.sh/

 cheat:gpg 
# Create a key
 gpg --gen-key


# Show keys
  To list a summary of all keys

    gpg --list-keys

  To show your public key

    gpg --armor --export

  To show the fingerprint for a key

    gpg --fingerprint KEY_ID

# Search for keys
  gpg --search-keys 'user@emailaddress.com'


# To Encrypt a File
  gpg --encrypt --recipient 'user@emailaddress.com' example.txt


# To Decrypt a File
  gpg --output example.txt --decrypt example.txt.gpg


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

  Where KEY_ID is the 8 character GPG key ID.

  Store these files to a safe location, such as a USB drive, then
  remove the private key file.

    shred -zu ~/private_key.txt

# Import keys
  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

# Revoke a key
  Create a revocation certificate.

    gpg --output ~/revoke.asc --gen-revoke KEY_ID

  Where KEY_ID is the 8 character GPG key ID.

  After creating the certificate import it.

    gpg --import ~/revoke.asc

  Then ensure that key servers know about the revokation.

    gpg --send-keys KEY_ID

# Signing and Verifying files
  If you are uploading files to launchpad you may also want to include
  a GPG signature file.

    gpg -ba filename

  or if you need to specify a particular key:

    gpg --default-key <key ID> -ba filename

  This then produces a file with a .asc extension which can be uploaded.
  If you need to set the default key more permanently then edit the
  file ~/.gnupg/gpg.conf and set the default-key parameter.

  To verify a downloaded file using its signature file.

  gpg --verify filename.asc

# Signing Public Keys
  Import the public key or retrieve it from a server.

    gpg --keyserver <keyserver> --recv-keys <Key_ID>

  Check its fingerprint against any previously stated value.

    gpg --fingerprint <Key_ID>

  Sign the key.

    gpg --sign-key <Key_ID>

  Upload the signed key to a server.

    gpg --keyserver <keyserver> --send-key <Key_ID>

# Change the email address associated with a GPG key
  gpg --edit-key <key ID>
  adduid

  Enter the new name and email address. You can then list the addresses with:

    list

  If you want to delete a previous email address first select it:

    uid <list number>

  Then delete it with:

    deluid

  To finish type:

    save

  Publish the key to a server:

    gpg --send-keys <key ID>

# Creating Subkeys
  Subkeys can be useful if you don't wish to have your main GPG key
  installed on multiple machines. In this way you can keep your
  master key safe and have subkeys with expiry periods or which may be
  separately revoked installed on various machines. This avoids
  generating entirely separate keys and so breaking any web of trust
  which has been established.

    gpg --edit-key <key ID>

  At the prompt type:

    addkey

  Choose RSA (sign only), 4096 bits and select an expiry period.
  Entropy will be gathered.

  At the prompt type:

    save

  You can also repeat the procedure, but selecting RSA (encrypt only).
  To remove the master key, leaving only the subkey/s in place:

    gpg --export-secret-subkeys <subkey ID> > subkeys
    gpg --export <key ID> > pubkeys
    gpg --delete-secret-key <key ID>

  Import the keys back.

    gpg --import pubkeys subkeys

  Verify the import.

    gpg -K

  Should show sec# instead of just sec.
  
# High-quality options for gpg for symmetric (secret key) encryption
  This is what knowledgable people consider a good set of options for 
  symmetric encryption with gpg to give you a high-quality result.
  
  gpg \
    --symmetric \
    --cipher-algo aes256 \
    --digest-algo sha512 \
    --cert-digest-algo sha512 \
    --compress-algo none -z 0 \
    --s2k-mode 3 \
    --s2k-digest-algo sha512 \
    --s2k-count 65011712 \
    --force-mdc \
    --pinentry-mode loopback \
    --armor \
    --no-symkey-cache \
    --output somefile.gpg \
    somefile # to encrypt
    
  gpg \
    --decrypt \
    --pinentry-mode loopback \
    --armor \
    --output somefile.gpg \
    somefile # to decrypt

 tldr:gpg 
# gpg
# GNU Privacy Guard.
# See `gpg2` for GNU Privacy Guard 2. Most operating systems symlink `gpg` to `gpg2`.
# More information: <https://gnupg.org>.

# Create a GPG public and private key interactively:
gpg --full-generate-key

# Sign `doc.txt` without encryption (writes output to `doc.txt.asc`):
gpg --clearsign doc.txt

# Encrypt and sign `doc.txt` for alice@example.com and bob@example.com (output to `doc.txt.gpg`):
gpg --encrypt --sign --recipient alice@example.com --recipient bob@example.com doc.txt

# Encrypt `doc.txt` with only a passphrase (output to `doc.txt.gpg`):
gpg --symmetric doc.txt

# Decrypt `doc.txt.gpg` (output to `stdout`):
gpg --decrypt doc.txt.gpg

# Import a public key:
gpg --import public.gpg

# Export public key for alice@example.com (output to `stdout`):
gpg --export --armor alice@example.com

# Export private key for alice@example.com (output to `stdout`):
gpg --export-secret-keys --armor alice@example.com

$

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