NAME | SYNOPSIS | DESCRIPTION | OPTIONS | BUGS | FILES | SEE ALSO | AVAILABILITY | COLOPHON

MCOOKIE(1)                      User Commands                     MCOOKIE(1)

NAME         top

       mcookie - generate magic cookies for xauth

SYNOPSIS         top

       mcookie [options]

DESCRIPTION         top

       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 /dev/urandom,
       /dev/random, or the libc pseudo-random functions, in this preference
       order.

OPTIONS         top

       -f, --file file
              Use this file as an additional source of randomness.  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.

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

BUGS         top

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

FILES         top

       /dev/urandom
       /dev/random

SEE ALSO         top

       md5sum(1), X(1), xauth(1), rand(3)

AVAILABILITY         top

       The mcookie command is part of the util-linux package and is
       available from Linux Kernel Archive 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.

COLOPHON         top

       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
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2017-03-13.  If you discover any rendering problems in this HTML ver‐
       sion 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 man‐
       ual page), send a mail to man-pages@man7.org

util-linux                      December 2014                     MCOOKIE(1)