1.\" Copyright (c) 2017 Netflix, Inc 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd May 22, 2017 28.Dt EFIVAR 8 29.Os 30.Sh NAME 31.Nm efivar 32.Nd UEFI environment variable interaction 33.Sh SYNOPSIS 34.Nm 35.Op Fl abdDHlLNpRtw 36.Op Fl n Ar name 37.Op Fl f Ar file 38.Op Fl -append 39.Op Fl -ascii 40.Op Fl -attributes 41.Op Fl -binary 42.Op Fl -delete 43.Op Fl -device-path 44.Op Fl -fromfile Ar file 45.Op Fl -guid 46.Op Fl -hex 47.Op Fl -list-guids 48.Op Fl -list 49.Op Fl -name Ar name 50.Op Fl -no-name 51.Op Fl -print 52.Op Fl -print-decimal 53.Op Fl -raw-guid 54.Op Fl -write 55.Sh DESCRIPTION 56This program manages 57.Dq Unified Extensible Firmware Interface 58.Pq UEFI 59environment variables. 60UEFI variables have three part: A namespace, a name and a value. 61The namespace is a GUID that is self assigned by the group defining the 62variables. 63The name is a Unicode name for the variable. 64The value is binary data. 65All Unicode data is presented to the user as UTF-8. 66.Pp 67The following options are available: 68.Bl -tag -width 20m 69.It Fl n Ar name Fl -name Ar name 70Specify the name of the variable to operate on. 71The 72.Ar name 73argument is the GUID of the variable, followed by a dash, followed by the 74UEFI variable name. 75The GUID may be in numeric format, or may be one of the well known 76symbolic name (see 77.Fl -list-guids 78for a complete list). 79.It Fl f Ar file Fl -fromfile Ar file 80When writing or appending to a variable, take the data for the 81variable's value from 82.Ar file 83instead of from the command line. 84This flag implies 85.Fl -write 86unless the 87.Fl -append 88flag is given. 89This behavior is not well understood and is currently unimplemented. 90.It Fl a Fl -append 91Append the specified value to the UEFI variable rather than replacing 92it. 93.It Fl t Ar attr Fl -attributes Ar attr 94Specify, in hexadecimal, the attributes for this 95variable. 96See section 7.2 (GetVariable subsection, Related Definitions) of the 97UEFI Specification for hex values to use. 98.It Fl A Fl -ascii 99Display the variable data as modified ascii: All printable characters 100are printed, while unprintable characters are rendered as a two-digit 101hexadecimal number preceded by a % character. 102.It Fl b Fl -binary 103Display the variable data as binary data. 104Usually will be used with the 105.Fl N 106or 107.Fl -no-name 108flag. 109Useful in scripts. 110.It Fl D Fl -delete 111Delete the specified variable. 112May not be used with either the 113.Fl -write 114or the 115.Fl -append 116flags. 117No 118.Ar value 119may be specified. 120.It Fl d Fl -device Fl -device-path 121Interpret the variables printed as UEFI device paths and print the 122UEFI standard string representation. 123.It Fl g Fl -guid 124flag is specified, guids are converted to names if they are known (and 125show up in 126.Fl -list-guids ). 127.It Fl H Fl -hex 128List variable data as a hex dump. 129.It Fl L Fl -list-guids 130Lists the well known GUIDs. 131The names listed here may be used in place of the numeric GUID values. 132These names will replace the numeric GUID values unless 133.Fl -raw-guid 134flag is specified. 135.It Fl l Fl -list 136List all the variables. 137If the 138.Fl -print 139flag is also listed, their values will be displayed. 140.It Fl N Fl -no-name 141Do not display the variable name. 142.It Fl p Fl -print 143Print the value of the variable. 144.It Fl R Fl -raw-guid 145Do not substitute well known names for GUID numeric values in output. 146.It Fl w Fl -write 147Write (replace) the variable specified with the value specified from 148standard input. 149No command line option to do this is available since UEFI variables 150are binary structures rather than strings. 151.Xr echo 1 152.Fl n 153can be used to specify simple strings. 154.It Ar name 155Display the 156.Ar name 157environment variable. 158.El 159.Sh COMPATIBILITY 160The 161.Nm 162program is intended to be compatible (strict superset) with a program 163of the same name included in the Red Hat libefivar package, 164but the 165.Fl d 166and 167.Fl -print-decimal 168flags are not implemented and never will be. 169.Pp 170The 171.Fl d 172flag is short for 173.Fl -device-path . 174.Sh SEE ALSO 175Appendix A of the UEFI specification has the format for GUIDs. 176All GUIDs 177.Dq Globally Unique Identifiers 178have the format described in RFC 4122. 179.Sh HISTORY 180The 181.Nm 182utility first appeared in 183.Fx 11.1 . 184