[apple/system_cmds.git] / nvram.tproj / nvram.8

.\"
.\" Copyright (c) 2000-2003 Apple Computer, Inc.  All rights reserved.
.\"
.TH nvram 8 "October 28, 2003"
.SH NAME
nvram \- manipulate firmware NVRAM variables
.SH SYNOPSIS
.B nvram
[
.B -p
] [
.B -f 
.IR filename
] [
.B -d 
.IR name
] [
.IR name
[=
.IR value
]] ...
.SH DESCRIPTION
The
.I nvram
command allows manipulation of firmware NVRAM variables.  It
can be used to get or set a variable.  It can also be used to print
all of the variables or set a list of variables from a file.
Changes to NVRAM variables are only saved by clean restart or shutdown.
.LP
In principle,
.IR name
can be any string.  In practice, not all strings will be accepted.
New World machines can create new variables as desired.  Some variables
require administrator privilege to get or set.
.LP
The given
.IR value
must match the data type required for
.IR name .
Binary data can be set using the %xx notation, where xx is the hex
value of the byte.  The type for new variables is always binary
data.
.SH OPTIONS
.\" ==========
.TP
.BI \-d " name"
Deletes the named firmware variable.
.\" ==========
.TP
.BI \-f " filename"
Set firmware variables from a text file.  The file must be a
list of "name value" statements.  The first space on each line
is taken to be the separator between "name" and "value".  If
the last character of a line is \\, the value extends to the next line.
.\" ==========
.TP
.B \-x
Use XML format for reading and writing variables.
This option must be used before the
.B \-p
or
.B \-f
options, since arguments are processed in order.
.TP
.B \-p
Print all of the firmware variables.
.SH EXAMPLES
.LP
.RS
example% nvram boot-args="-s rd=*hd:10"
.RE
.LP
Set the boot-args variable to "-s rd=*hd:10".  This would specify
single user mode with the root device in hard drive partition 10.
.LP
.RS
example% nvram my-variable="String One%00String Two%00%00"
.RE
.LP
Create a new variable, my-variable, containing a list of two
C-strings that is terminated by a NUL.
.LP
.RS
example% nvram -d my-variable
.RE
.LP
Deletes the variable named my-variable.
.PD
Commit	Line	Data
1815bff5	1	.\"
83f6dbe8	2	.\" Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
1815bff5	3	.\"
83f6dbe8	4	.TH nvram 8 "October 28, 2003"
1815bff5	5	.SH NAME
4c00c0ae	6	nvram \- manipulate firmware NVRAM variables
1815bff5 A	7	.SH SYNOPSIS
	8	.B nvram
	9	[
	10	.B -p
	11	] [
	12	.B -f
	13	.IR filename
	14	] [
83f6dbe8	15	.B -d
1815bff5	16	.IR name
83f6dbe8 A	17	] [
	18	.IR name
	19	[=
1815bff5	20	.IR value
83f6dbe8	21	]] ...
1815bff5 A	22	.SH DESCRIPTION
	23	The
	24	.I nvram
4c00c0ae	25	command allows manipulation of firmware NVRAM variables. It
1815bff5 A	26	can be used to get or set a variable. It can also be used to print
1815bff5 A	27	all of the variables or set a list of variables from a file.
c3a08f59	28	Changes to NVRAM variables are only saved by clean restart or shutdown.
1815bff5 A	29	.LP
	30	In principle,
	31	.IR name
	32	can be any string. In practice, not all strings will be accepted.
b51d5b5f A	33	New World machines can create new variables as desired. Some variables
b51d5b5f A	34	require administrator privilege to get or set.
1815bff5 A	35	.LP
	36	The given
	37	.IR value
	38	must match the data type required for
	39	.IR name .
	40	Binary data can be set using the %xx notation, where xx is the hex
	41	value of the byte. The type for new variables is always binary
	42	data.
1815bff5	43	.SH OPTIONS
34d340d7	44	.\" ==========
1815bff5	45	.TP
34d340d7 A	46	.BI \-d " name"
	47	Deletes the named firmware variable.
	48	.\" ==========
1815bff5 A	49	.TP
1815bff5 A	50	.BI \-f " filename"
4c00c0ae	51	Set firmware variables from a text file. The file must be a
34d340d7 A	52	list of "name value" statements. The first space on each line
	53	is taken to be the separator between "name" and "value". If
	54	the last character of a line is \\, the value extends to the next line.
	55	.\" ==========
83f6dbe8	56	.TP
34d340d7 A	57	.B \-x
	58	Use XML format for reading and writing variables.
	59	This option must be used before the
	60	.B \-p
	61	or
	62	.B \-f
	63	options, since arguments are processed in order.
	64	.TP
	65	.B \-p
	66	Print all of the firmware variables.
1815bff5 A	67	.SH EXAMPLES
	68	.LP
	69	.RS
	70	example% nvram boot-args="-s rd=*hd:10"
	71	.RE
	72	.LP
b51d5b5f	73	Set the boot-args variable to "-s rd=*hd:10". This would specify
1815bff5 A	74	single user mode with the root device in hard drive partition 10.
	75	.LP
	76	.RS
	77	example% nvram my-variable="String One%00String Two%00%00"
	78	.RE
	79	.LP
b51d5b5f	80	Create a new variable, my-variable, containing a list of two
1815bff5	81	C-strings that is terminated by a NUL.
83f6dbe8 A	82	.LP
	83	.RS
	84	example% nvram -d my-variable
	85	.RE
	86	.LP
	87	Deletes the variable named my-variable.
1815bff5	88	.PD