1MCOOKIE(1) User Commands MCOOKIE(1)
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6 mcookie - generate magic cookies for xauth
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9 mcookie [options]
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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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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 -V, --version
43 Display version information and exit.
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45 -h, --help
46 Display help text and exit.
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49 /dev/urandom
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51 /dev/random
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54 It is assumed that none of the randomness sources will block.
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57 md5sum(1), X(7), xauth(1), rand(3)
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60 For bug reports, use the issue tracker at
61 https://github.com/karelzak/util-linux/issues.
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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 2.37.2 2021-06-02 MCOOKIE(1)