openssl genrsa -help

saolasosme

Generation of RSA Private Key. Superseded by genpkey(1).

$ openssl genrsa -help
Usage: genrsa [options]
Valid options are:
 -help               Display this summary
 -3                  Use 3 for the E value
 -F4                 Use F4 (0x10001) for the E value
 -f4                 Use F4 (0x10001) for the E value
 -out outfile        Output the key to specified file
 -rand val           Load the file(s) into the random number generator
 -writerand outfile  Write random data to the specified file
 -passout val        Output file pass phrase source
 -*                  Encrypt the output with any supported cipher
 -engine val         Use engine, possibly a hardware device
 -primes +int        Specify number of primes