arc4random_uniform - Linux


arc4random_uniform is a command-line utility that generates random numbers using the arc4random algorithm. It is primarily used to generate pseudo-random numbers for various cryptographic and statistical purposes.


arc4random_uniform [range]


  • range: The upper bound of the range from which to generate a random number. If not specified, the default range is 100.


Generating a Random Number in Range 0-99


Generating a Random Number in Range 1-10

arc4random_uniform 10

Common Issues

  • Seed Predictability: The arc4random algorithm is not cryptographically secure and should not be used for applications requiring high levels of security.
  • Unexpected Output: If the specified range is negative or zero, arc4random_uniform will generate an error.


arc4random_uniform can be integrated with other Linux commands for more advanced tasks. For example, it can be used to generate random password strings:

echo "$(arc4random_uniform 10000)" | md5sum | cut -c10-19

Related Commands

  • random: Generates random numbers from /dev/urandom for cryptographic purposes.
  • openssl rand: Provides a more secure and versatile random number generator.