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MCOOKIE
Section: User Commands (1)Updated: December 2014
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NAME
mcookie - generate magic cookies for xauthSYNOPSIS
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 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
It is assumed that none of the randomness sources will block.FILES
/dev/urandom/dev/random
SEE ALSO
md5sum(1), X(1), xauth(1), rand(3)AVAILABILITY
The mcookie command is part of the util-linux package and is available from Linux Kernel Archive