Usage: /usr/bin/efi-updatevar: [-a] [-e] [-d <list>[-<entry>]] [-k <key>] [-g <guid>] [-b <file>|-f <file>|-c file] <var>
Manipulate the UEFI key database via the efivarfs filesystem

Options:
	-a	append a value to the variable instead of replacing it
	-e	use EFI Signature List instead of signed update (only works in Setup Mode
	-b <binfile>	Add hash of <binfile> to the signature list
	-f <file>	Add or Replace the key file (.esl or .auth) to the <var>
	-c <file>	Add or Replace the x509 certificate to the <var> (with <guid> if provided)
	-g <guid>	Optional <guid> for the X509 Certificate
	-k <key>	Secret key file for authorising User Mode updates
	-d <list>[-<entry>]	Delete the signature list <list> (or just a single <entry> within the list)
	--engine <eng>	Use engine <eng> for private key