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

.\"
.\" Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
.\"
.TH nvram 8 "December 12, 2000"
.SH NAME
nvram \- manipulate Open Firmware NVRAM variables
.SH SYNOPSIS
.B nvram
[
.B -p
] [
.B -f 
.IR filename
] [
.IR name
] [=
.IR value
] ...
.SH DESCRIPTION
The
.I nvram
command allows manipulation of Open 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.
.LP
In principle,
.IR name
can be any string.  In practice, not all strings will be accepted.
Old world machines have a fixed set of Open Firmware variables.
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.
.LP
Two Open Firmware variables have special treatment on old world
machines:
.IR boot-command
and
.IR boot-args .
As long as
.IR boot-command
starts with "# bootr," the
.IR boot-args
variable will be present.  Getting or setting
.IR boot-args
will get or set the
.IR boot-command
while preserving the "# bootr".  In most cases when setting boot arguments 
for the kernel, there is no need to test for old world and set
.IR boot-command .
Instead set
.IR boot-args
with the desired arguments.
.SH OPTIONS
.TP
.B \-p
Print all of the Open Firmware variables.
.TP
.BI \-f " filename"
Set Open Firmware variables from a text file.  The file must be a
list name=value statements.  If the last character of a line is
\\, the value will be continued to the next line.
.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.
.SH FILES
.PD 0
.TP 30
.B /usr/share/nvram
Files containing patches for old world machines.
.PD
Commit	Line	Data
1815bff5 A	1	.\"
	2	.\" Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	.\"
	4	.TH nvram 8 "December 12, 2000"
	5	.SH NAME
	6	nvram \- manipulate Open Firmware NVRAM variables
	7	.SH SYNOPSIS
	8	.B nvram
	9	[
	10	.B -p
	11	] [
	12	.B -f
	13	.IR filename
	14	] [
	15	.IR name
	16	] [=
	17	.IR value
	18	] ...
	19	.SH DESCRIPTION
	20	The
	21	.I nvram
	22	command allows manipulation of Open Firmware NVRAM variables. It
	23	can be used to get or set a variable. It can also be used to print
	24	all of the variables or set a list of variables from a file.
	25	.LP
	26	In principle,
	27	.IR name
	28	can be any string. In practice, not all strings will be accepted.
	29	Old world machines have a fixed set of Open Firmware variables.
b51d5b5f A	30	New World machines can create new variables as desired. Some variables
b51d5b5f A	31	require administrator privilege to get or set.
1815bff5 A	32	.LP
	33	The given
	34	.IR value
	35	must match the data type required for
	36	.IR name .
	37	Binary data can be set using the %xx notation, where xx is the hex
	38	value of the byte. The type for new variables is always binary
	39	data.
	40	.LP
	41	Two Open Firmware variables have special treatment on old world
	42	machines:
	43	.IR boot-command
	44	and
	45	.IR boot-args .
	46	As long as
	47	.IR boot-command
	48	starts with "# bootr," the
	49	.IR boot-args
	50	variable will be present. Getting or setting
	51	.IR boot-args
	52	will get or set the
	53	.IR boot-command
	54	while preserving the "# bootr". In most cases when setting boot arguments
	55	for the kernel, there is no need to test for old world and set
	56	.IR boot-command .
	57	Instead set
	58	.IR boot-args
	59	with the desired arguments.
	60	.SH OPTIONS
	61	.TP
	62	.B \-p
	63	Print all of the Open Firmware variables.
	64	.TP
	65	.BI \-f " filename"
	66	Set Open Firmware variables from a text file. The file must be a
	67	list name=value statements. If the last character of a line is
	68	\\, the value will be continued to the next line.
	69	.SH EXAMPLES
	70	.LP
	71	.RS
	72	example% nvram boot-args="-s rd=*hd:10"
	73	.RE
	74	.LP
b51d5b5f	75	Set the boot-args variable to "-s rd=*hd:10". This would specify
1815bff5 A	76	single user mode with the root device in hard drive partition 10.
	77	.LP
	78	.RS
	79	example% nvram my-variable="String One%00String Two%00%00"
	80	.RE
	81	.LP
b51d5b5f	82	Create a new variable, my-variable, containing a list of two
1815bff5 A	83	C-strings that is terminated by a NUL.
	84	.SH FILES
	85	.PD 0
	86	.TP 30
	87	.B /usr/share/nvram
	88	Files containing patches for old world machines.
	89	.PD