NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | BUGS | SEE ALSO | REPORTING BUGS | AVAILABILITY |
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MCOOKIE(1) User Commands MCOOKIE(1)
mcookie - generate magic cookies for xauth
mcookie [options]
mcookie generates a 128-bit random hexadecimal number for use with the X authority system. Typical usage: xauth add :0 . mcookie The "random" number generated is actually the MD5 message digest of random information coming from one of the sources getrandom(2) system call, /dev/urandom, /dev/random, or the libc pseudo-random functions, in this preference order. See also the option --file.
-f, --file file Use this file as an additional source of randomness (for example /dev/urandom). When file is '-', characters are read from standard input. -m, --max-size number Read from file only this number of bytes. This option is meant to be used when reading additional randomness from a file or device. The number argument may be followed by the multiplicative suffixes KiB=1024, MiB=1024*1024, and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB=1000, MB=1000*1000, and so on for GB, TB, PB, EB, ZB and YB. -v, --verbose Inform where randomness originated, with amount of entropy read from each source. -h, --help Display help text and exit. -V, --version Print version and exit.
/dev/urandom /dev/random
It is assumed that none of the randomness sources will block.
md5sum(1), X(7), xauth(1), rand(3)
For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.
The mcookie command is part of the util-linux package which can
be downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>. This page
is part of the util-linux (a random collection of Linux
utilities) project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have
a bug report for this manual page, send it to
[email protected]. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-06-10.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in
this COLOPHON (which is not part of the original manual page),
send a mail to [email protected]
util-linux 2.39.594-1e0ad 2023-07-19 MCOOKIE(1)