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 abdDHlLNpRtuw 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 -utf8 55.Op Fl -write 56.Sh DESCRIPTION 57This program manages 58.Dq Unified Extensible Firmware Interface 59.Pq UEFI 60environment variables. 61UEFI variables have three part: A namespace, a name and a value. 62The namespace is a GUID that is self assigned by the group defining the 63variables. 64The name is a Unicode name for the variable. 65The value is binary data. 66All Unicode data is presented to the user as UTF-8. 67.Pp 68The following options are available: 69.Bl -tag -width 20m 70.It Fl n Ar name Fl -name Ar name 71Specify the name of the variable to operate on. 72The 73.Ar name 74argument is the GUID of the variable, followed by a dash, followed by the 75UEFI variable name. 76The GUID may be in numeric format, or may be one of the well known 77symbolic name (see 78.Fl -list-guids 79for a complete list). 80.It Fl f Ar file Fl -fromfile Ar file 81When writing or appending to a variable, take the data for the 82variable's value from 83.Ar file 84instead of from the command line. 85This flag implies 86.Fl -write 87unless the 88.Fl -append 89flag is given. 90This behavior is not well understood and is currently unimplemented. 91.It Fl a Fl -append 92Append the specified value to the UEFI variable rather than replacing 93it. 94.It Fl t Ar attr Fl -attributes Ar attr 95Specify, in hexadecimal, the attributes for this 96variable. 97See section 7.2 (GetVariable subsection, Related Definitions) of the 98UEFI Specification for hex values to use. 99.It Fl A Fl -ascii 100Display the variable data as modified ascii: All printable characters 101are printed, while unprintable characters are rendered as a two-digit 102hexadecimal number preceded by a % character. 103.It Fl b Fl -binary 104Display the variable data as binary data. 105Usually will be used with the 106.Fl N 107or 108.Fl -no-name 109flag. 110Useful in scripts. 111.It Fl D Fl -delete 112Delete the specified variable. 113May not be used with either the 114.Fl -write 115or the 116.Fl -append 117flags. 118No 119.Ar value 120may be specified. 121.It Fl d Fl -device Fl -device-path 122Interpret the variables printed as UEFI device paths and print the 123UEFI standard string representation. 124.It Fl g Fl -guid 125flag is specified, guids are converted to names if they are known (and 126show up in 127.Fl -list-guids ). 128.It Fl H Fl -hex 129List variable data as a hex dump. 130.It Fl L Fl -list-guids 131Lists the well known GUIDs. 132The names listed here may be used in place of the numeric GUID values. 133These names will replace the numeric GUID values unless 134.Fl -raw-guid 135flag is specified. 136.It Fl l Fl -list 137List all the variables. 138If the 139.Fl -print 140flag is also listed, their values will be displayed. 141.It Fl N Fl -no-name 142Do not display the variable name. 143.It Fl p Fl -print 144Print the value of the variable. 145.It Fl R Fl -raw-guid 146Do not substitute well known names for GUID numeric values in output. 147.It Fl u Fl -utf8 148Treat the value of the variable as UCS2 and convert it to UTF8 and 149print the result. 150.It Fl w Fl -write 151Write (replace) the variable specified with the value specified from 152standard input. 153No command line option to do this is available since UEFI variables 154are binary structures rather than strings. 155.Xr echo 1 156.Fl n 157can be used to specify simple strings. 158.It Ar name 159Display the 160.Ar name 161environment variable. 162.El 163.Sh COMPATIBILITY 164The 165.Nm 166program is intended to be compatible (strict superset) with a program 167of the same name included in the Red Hat libefivar package, 168but the 169.Fl d 170and 171.Fl -print-decimal 172flags are not implemented and never will be. 173.Pp 174The 175.Fl d 176flag is short for 177.Fl -device-path . 178.Sh SEE ALSO 179Appendix A of the UEFI specification has the format for GUIDs. 180All GUIDs 181.Dq Globally Unique Identifiers 182have the format described in RFC 4122. 183.Sh HISTORY 184The 185.Nm 186utility first appeared in 187.Fx 11.1 . 188