Section: User Commands (1)
Updated: December 2014
mcookie - generate magic cookies for xauth
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
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.
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
- -V, --version
Display version information and exit.
- -h, --help
Display help text and exit.
It is assumed that none of the randomness sources will block.
The mcookie command is part of the util-linux package and is available from
Linux Kernel Archive