NAME¶mcookie - generate magic cookies for xauth
DESCRIPTION¶mcookie generates a 128-bit random hexadecimal number for use with the X authority system. Typical usage:
The "random" number generated is actually the MD5 message digest of random information coming from one of the sources getrandom() 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.
- -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.
SEE ALSO¶md5sum(1), X(7), xauth(1), rand(3)
AVAILABILITY¶The mcookie command is part of the util-linux package and is available from Linux Kernel Archive.