---
name: "efivar"
section: "8"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/efivar/8"
---

# efivar(8)

UEFI environment variable interaction

## NAME

**efivar** – UEFI environment variable interaction

## SYNOPSIS

**efivar** \[**-abdDHlLNpqRtuw**\] \[**-n** *name*\] \[**-f** *file*\] \[**--append**\] \[**--ascii**\] \[**--attributes**\] \[**--binary**\] \[**--delete**\] \[**--device-path**\] \[**--fromfile** *file*\] \[**--guid**\] \[**--hex**\] \[**--list-guids**\] \[**--list**\] \[**--load-option**\] \[**--name** *name*\] \[**--no-name**\] \[**--print**\] \[**--print-decimal**\] \[**--quiet**\] \[**--raw-guid**\] \[**--utf8**\] \[**--write**\]

## DESCRIPTION

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.

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, 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)](/echo/1.md) **-n** can be used to specify simple strings.

- *name*

  Display the *name* environment variable.

## COMPATIBILITY

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**.

## SEE ALSO

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

## HISTORY

The **efivar** utility first appeared in FreeBSD 11.1.