1MCOOKIE(1)                       User Commands                      MCOOKIE(1)
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NAME

6       mcookie - generate magic cookies for xauth
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SYNOPSIS

9       mcookie [options]
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DESCRIPTION

12       mcookie  generates a 128-bit random hexadecimal number for use with the
13       X authority system.  Typical usage:
14              xauth add :0 . `mcookie`
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16       The "random" number generated is actually the output of the MD5 message
17       digest fed with various pieces of random information: the current time,
18       the process id, the parent process id, and optionally the  contents  of
19       an  input  file. and several bytes of information from the first of the
20       following devices which is present: /dev/random, /dev/urandom, files in
21       /proc, /dev/audio.
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OPTIONS

24       -f, --file=FILE
25              Use  file  as  a  macig cookie seed. When file is defined as `-'
26              character input is read from stdin.
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28       -v, --verbose
29              Explain what is being done.
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31       -V, --version
32              Output version information and exit.
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34       -h, --help
35              Display this help and exit.
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BUGS

38       The entropy in the generated 128-bit  is  probably  quite  small  (and,
39       therefore,  vulnerable to attack) unless a non-pseudorandom number gen‐
40       erator is used (e.g., /dev/random under Linux).
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42       It is assumed that none of the devices opened will block.
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FILES

45       /dev/random
46       /dev/urandom
47       /dev/audio
48       /proc/stat
49       /proc/loadavg
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SEE ALSO

52       X(1), xauth(1), md5sum(1)
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AVAILABILITY

55       The mcookie command is part of the util-linux package and is  available
56       from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
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60util-linux                         June 2011                        MCOOKIE(1)