Generate a new keypair:

user@tokyo:~$ gpg --gen-key

Export public key:

user@tokyo:~$ gpg --armor --output pubkey.pgp --export my@mail.de

List keys:

user@tokyo:~$ gpg --list-keys

Sign a file:

user@tokyo:~$ gpg --output file.asc --detach-sig file

Verify a file:

user@tokyo:~$ gpg --verify file.sig file

Clearsign a text file:

user@tokyo:~$ gpg --clearsign file.txt

Verify a clearsigned text file:

user@tokyo:~$ gpg --verify file.txt.asc file