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EFIVAR(8)		FreeBSD	System Manager's Manual		     EFIVAR(8)

     efivar -- UEFI environment	variable interaction

     efivar [-abdDHlLNpRtw] [-n	name] [-f file]	[--append] [--ascii]
	    [--attributes] [--binary] [--delete] [--device-path]
	    [--fromfile	file] [--guid] [--hex] [--list-guids] [--list]
	    [--name name] [--no-name] [--print]	[--print-decimal] [--raw-guid]

     This program manages ``Unified Extensible Firmware	Interface'' (UEFI)
     environment variables.  UEFI variables have three part: A namespace, a
     name and a	value.	The namespace is a GUID	that is	self assigned by the
     group defining the	variables.  The	name is	a Unicode name for the vari-
     able.  The	value is binary	data.  All Unicode data	is presented to	the
     user as UTF-8.

     The following options are available:

     -n	name --name name   Specify the name of the variable to operate on.
			   The name argument is	the GUID of the	variable, fol-
			   lowed by a dash, followed by	the UEFI variable
			   name.  The GUID may be in numeric format, or	may be
			   one of the well known symbolic name (see
			   --list-guids	for a complete list).

     -f	file --fromfile	file
			   When	writing	or appending to	a variable, take the
			   data	for the	variable's value from file instead of
			   from	the command line.  This	flag implies --write
			   unless the --append flag is given.  This behavior
			   is not well understood and is currently unimple-

     -a	--append	   Append the specified	value to the UEFI variable
			   rather than replacing it.

     -t	attr --attributes attr
			   Specify, in hexadecimal, the	attributes for this
			   variable.  See section 7.2 (GetVariable subsection,
			   Related Definitions)	of the UEFI Specification for
			   hex values to use.

     -A	--ascii		   Display the variable	data as	modified ascii:	All
			   printable characters	are printed, while unprintable
			   characters are rendered as a	two-digit hexadecimal
			   number preceded by a	% character.

     -b	--binary	   Display the variable	data as	binary data.  Usually
			   will	be used	with the -N or --no-name flag.	Useful
			   in scripts.

     -D	--delete	   Delete the specified	variable.  May not be used
			   with	either the --write or the --append flags.  No
			   value may be	specified.

     -d	--device --device-path
			   Interpret the variables printed as UEFI device
			   paths and print the UEFI standard string represen-

     -g	--guid		   flag	is specified, guids are	converted to names if
			   they	are known (and show up in --list-guids -).

     -H	--hex		   List	variable data as a hex dump.

     -L	--list-guids	   Lists the well known	GUIDs.	The names listed here
			   may be used in place	of the numeric GUID values.
			   These names will replace the	numeric	GUID values
			   unless --raw-guid flag is specified.

     -l	--list		   List	all the	variables.  If the --print flag	is
			   also	listed,	their values will be displayed.

     -N	--no-name	   Do not display the variable name.

     -p	--print		   Print the value of the variable.

     -R	--raw-guid	   Do not substitute well known	names for GUID numeric
			   values in output.

     -w	--write		   Write (replace) the variable	specified with the
			   value specified from	standard input.	 No command
			   line	option to do this is available since UEFI
			   variables are binary	structures rather than
			   strings.  echo(1) -n	can be used to specify simple

     name		   Display the name environment	variable.

     The efivar	program	is intended to be compatible (strict superset) with a
     program of	the same name included in the Red Hat libefivar	package, but
     the -d and	--print-decimal	flags are not implemented and never will be.

     The -d flag is short for --device-path.

     Appendix A	of the UEFI specification has the format for GUIDs.  All GUIDs
     ``Globally	Unique Identifiers'' have the format described in RFC 4122.

     The efivar	utility	first appeared in FreeBSD 11.1.

FreeBSD	11.1			 May 22, 2017			  FreeBSD 11.1


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