This program manages
"Unified Extensible Firmware Interface"
(UEFI)
environment variables.
UEFI variables have three parts: 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 variable.
The value is binary data.
All Unicode data is presented to the user as UTF-8.
| -n name --name name
|
| |
Specify the name of the variable to operate on.
The
name
argument is the GUID of the variable, followed 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 names (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
or
--print
flags are given.
This behavior is not well understood and is currently unimplemented
for writes.
When
--print
is specified, the contents of the file are used as the value to
print using any other specified flags.
This is used primarily for testing purposes for more complicated
variable decoding.
|
| -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 representation.
|
| -g --guid
|
| |
Convert GUIDs to names if they are known
(and show them 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 the
--raw-guid
flag is specified.
|
| -l --list
|
| |
List all the variables.
If the
--print
flag is also listed, their values will be displayed.
|
| --load-option
|
| |
Decode the variable as if it were a UEFI Boot Option, including information
about what device and/or paths the UEFI DevicePaths decode to.
|
| -N --no-name
|
| |
Do not display the variable name.
|
| -p --print
|
| |
Print the value of the variable.
|
| -q --quiet
|
| |
When an error occurs, exit with a non-zero value without outputting
any error messages.
Otherwise, produce the normal output and exit with a zero status.
|
| -R --raw-guid
|
| |
Do not substitute well known names for GUID numeric values in output.
|
| -u --utf8
|
| |
Treat the value of the variable as UCS2 and convert it to UTF8 and
print the result.
|
| -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 strings.
|
| name
|
Display the
name
environment variable.
|
|
