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:
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15          xauth add :0 . mcookie
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17       The "random" number generated is actually the MD5 message digest of
18       random information coming from one of the sources getrandom(2) system
19       call, /dev/urandom, /dev/random, or the libc pseudo-random functions,
20       in this preference order. See also the option --file.
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OPTIONS

23       -f, --file file
24           Use this file as an additional source of randomness (for example
25           /dev/urandom). When file is '-', characters are read from standard
26           input.
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28       -m, --max-size number
29           Read from file only this number of bytes. This option is meant to
30           be used when reading additional randomness from a file or device.
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32           The number argument may be followed by the multiplicative suffixes
33           KiB=1024, MiB=1024*1024, and so on for GiB, TiB, PiB, EiB, ZiB and
34           YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB")
35           or the suffixes KB=1000, MB=1000*1000, and so on for GB, TB, PB,
36           EB, ZB and YB.
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38       -v, --verbose
39           Inform where randomness originated, with amount of entropy read
40           from each source.
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42       -h, --help
43           Display help text and exit.
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45       -V, --version
46           Print version and exit.
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FILES

49       /dev/urandom
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51       /dev/random
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BUGS

54       It is assumed that none of the randomness sources will block.
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SEE ALSO

57       md5sum(1), X(7), xauth(1), rand(3)
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REPORTING BUGS

60       For bug reports, use the issue tracker at
61       https://github.com/util-linux/util-linux/issues.
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AVAILABILITY

64       The mcookie command is part of the util-linux package which can be
65       downloaded from Linux Kernel Archive
66       <https://www.kernel.org/pub/linux/utils/util-linux/>.
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70util-linux 2.38                   2022-02-17                        MCOOKIE(1)
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