Section: User Commands (1)
Updated: June 2011
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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 output of the MD5 message
digest fed with various pieces of random information: the current time, the
process id, the parent process id, and optionally the contents of an input
file. and several bytes of information from the first of the following
devices which is present:
- -f, --file=FILE
Use file as a macig cookie seed. When file is defined as `-' character
input is read from stdin.
- -v, --verbose
Explain what is being done.
- -V, --version
Output version information and exit.
- -h, --help
Display this help and exit.
The entropy in the generated 128-bit is probably quite small (and,
therefore, vulnerable to attack) unless a non-pseudorandom number generator
is used (e.g.,
It is assumed that none of the devices opened will block.
The mcookie command is part of the util-linux package and is available from
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using the manual pages.
Time: 05:32:57 GMT, January 24, 2018