mcookie
(1)generate magic cookies for xauth
Options
5-f--filefileUse this file as an additional source of randomness (for example /dev/urandom). When file is '-', characters are read from standard input.
-m--max-sizenumberRead 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--verboseInform where randomness originated, with amount of entropy read from each source.
-h--helpDisplay help text and exit.
-V--versionDisplay version and exit.
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 getrandom(2) system call, /dev/urandom, /dev/random, or the libc pseudo-random functions, in this preference order. See also the option --file.
FILES
BUGS
REPORTING BUGS
For bug reports, use the issue tracker https://github.com/util-linux/util-linux/issues.
AVAILABILITY
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/.