nvram.tproj/nvram.8

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