deb:
=====
[root@pi /]# rngd --help
Usage: rngd [OPTION...]
Check and feed random data from hardware device to kernel entropy pool.

  -b, --background           Become a daemon (default)
  -d, --no-drng=1|0          Do not use drng as a source of random number input
                             (default: 0)
  -f, --foreground           Do not fork and become a daemon
  -n, --no-tpm=1|0           Do not use tpm as a source of random number input
                             (default: 0)
  -o, --random-device=file   Kernel device used for random number output
                             (default: /dev/random)
  -p, --pid-file=file        File used for recording daemon PID, and multiple
                             exclusion (default: /var/run/rngd.pid)
  -q, --quiet                Suppress error messages
  -r, --rng-device=file      Kernel device used for random number input
                             (default: /dev/hwrng)
  -s, --random-step=nnn      Number of bytes written to random-device at a time
                             (default: 64)
  -v, --verbose              Report available entropy sources
  -W, --fill-watermark=n     Do not stop feeding entropy to random-device until
                             at least n bits of entropy are available in the
                             pool (default: 2048), 0 <= n <= 4096
  -?, --help                 Give this help list
      --usage                Give a short usage message
  -V, --version              Print program version

Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.

Report bugs to Jeff Garzik <[email protected]>.


arch:
=====
[root@pikvm ~]# rngd --help
Usage: rngd [OPTION...]
Check and feed random data from hardware device to kernel entropy pool.

  -b, --background           Become a daemon (default)
  -d, --debug                Enable debug output
  -D, --drop-privileges=user:group
                             Drop privileges to a user and group specified
  -e, --entropy-count=n      Number of entropy bits to support (default: 8), 1
                             <= n <= 8
  -f, --foreground           Do not fork and become a daemon
  -i, --ignorefail           Ignore repeated fips failures
  -l, --list                 List the operational entropy sources on this
                             system and exit
  -n, --include=n            Enable the numbered entropy source specified
  -o, --random-device=file   Kernel device used for random number output
                             (default: /dev/random)
  -O, --option=options       rng specific options in the form source:key:value
  -p, --pid-file=file        File used for recording daemon PID, and multiple
                             exclusion (default: /var/run/rngd.pid)
  -q, --quiet                Suppress all messages
  -r, --rng-device=file      Kernel device used for random number input
                             (default: /dev/hwrng)
  -R, --force-reseed=n       Time in seconds to force adding entropy to the
                             random device
  -s, --random-step=nnn      Number of bytes written to random-device at a time
                             (default: 64)
  -t, --test                 Enter test mode and report entropy production
                             rates
  -u, --use-slow-sources     Always gather entropy from sources considered as
                             "slow" too
  -W, --fill-watermark=n     Do not stop feeding entropy to random-device until
                             at least n bits of entropy are available in the
                             pool (default: 3/4 of poolsize), 0 <= n <= 256
  -x, --exclude=n            Disable the numbered entropy source specified
  -?, --help                 Give this help list
      --usage                Give a short usage message
  -v, --version              List rngd version

Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.

Report bugs to Neil Horman <[email protected]>.