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 .IR name
  19 [=
  20 .IR value
  21 ]] ...
  22 .SH DESCRIPTION
  23 The
  24 .I nvram
  25 command allows manipulation of firmware NVRAM variables.  It
  26 can be used to get or set a variable.  It can also be used to print
  27 all of the variables or set a list of variables from a file.
  28 Changes to NVRAM variables are only saved by clean restart or shutdown.
  29 .LP
  30 In principle,
  31 .IR name
  32 can be any string.  In practice, not all strings will be accepted.
  33 New World machines can create new variables as desired.  Some variables
  34 require administrator privilege to get or set.
  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.
  43 .SH OPTIONS
  44 .\" ==========
  45 .TP
  46 .BI \-d " name"
  47 Deletes the named firmware variable.
  48 .\" ==========
  49 .TP
  50 .BI \-f " filename"
  51 Set firmware variables from a text file.  The file must be 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 .\" ==========
  56 .TP
  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.
  67 .SH EXAMPLES
  68 .LP
  69 .RS
  70 example% nvram boot-args="-s rd=*hd:10"
  71 .RE
  72 .LP
  73 Set the boot-args variable to "-s rd=*hd:10".  This would specify
  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
  80 Create a new variable, my-variable, containing a list of two
  81 C-strings that is terminated by a NUL.
  82 .LP
  83 .RS
  84 example% nvram -d my-variable
  85 .RE
  86 .LP
  87 Deletes the variable named my-variable.
  88 .PD