mcookie Man page

MCOOKIE(1) User Commands MCOOKIE(1)

NAME

mcookie – generate magic cookies for xauth

SYNOPSIS

mcookie [options]

DESCRIPTION

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

-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 suf‐
fixes 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 mean‐
ing 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

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

FILES
/dev/urandom
/dev/random

SEE ALSO

X, xauth, md5sum, rand(3)

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

util-linux December 2014 MCOOKIE(1)

Ils en parlent aussi

: Mmm, cookies! | Inconsolation