misc-utils/mcookie.1

   1 .\" mcookie.1 --
   2 .\" Public Domain 1995 Rickard E. Faith (faith@cs.unc.edu)
   3 .TH MCOOKIE 1 "December 2014" "util-linux" "User Commands"
   4 .SH NAME
   5 mcookie \- generate magic cookies for xauth
   6 .SH SYNOPSIS
   7 .B mcookie
   8 [options]
   9 .SH DESCRIPTION
  10 .B mcookie
  11 generates a 128-bit random hexadecimal number for use with the X authority
  12 system.  Typical usage:
  13 .sp
  14 .RS
  15 .B xauth add :0 . `mcookie`
  16 .RE
  17 .PP
  18 The "random" number generated is actually the MD5 message
  19 digest of random information coming from one of the sources
  20 .IR getrandom ()
  21 system call,
  22 .IR /dev/urandom ,
  23 .IR /dev/random ,
  24 or the
  25 .IR "libc pseudo-random functions" ,
  26 in this preference order. See also the option \fB\-\-file\fR.
  27 .SH OPTIONS
  28 .TP
  29 .BR \-f , " \-\-file " \fIfile
  30 Use this \fIfile\fR as an additional source of randomness (for example /dev/urandom).
  31 When \fIfile\fR is '-', characters are read from standard input.
  32 .TP
  33 .BR \-m , " \-\-max\-size " \fInumber
  34 Read from \fIfile\fR only this \fInumber\fR of bytes.
  35 This option is meant to be used when reading additional
  36 randomness from a file or device.
  37 .IP
  38 The
  39 .I number
  40 argument may be followed by the multiplicative suffixes KiB=1024,
  41 MiB=1024*1024, and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is
  42 optional, e.g., "K" has the same meaning as "KiB") or the suffixes
  43 KB=1000, MB=1000*1000, and so on for GB, TB, PB, EB, ZB and YB.
  44 .TP
  45 .BR \-v , " \-\-verbose"
  46 Inform where randomness originated, with amount of entropy read from each
  47 source.
  48 .TP
  49 .BR \-V , " \-\-version"
  50 Display version information and exit.
  51 .TP
  52 .BR \-h , " \-\-help"
  53 Display help text and exit.
  54 .SH FILES
  55 .I /dev/urandom
  56 .br
  57 .I /dev/random
  58 .SH BUGS
  59 It is assumed that none of the randomness sources will block.
  60 .SH SEE ALSO
  61 .BR md5sum (1),
  62 .BR X (7),
  63 .BR xauth (1),
  64 .BR rand (3)
  65 .SH AVAILABILITY
  66 The mcookie command is part of the util-linux package and is available from
  67 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
  68 Linux Kernel Archive
  69 .UE .