factor, primes – factor a number, generate large primes

factor [ number ]

primes start [ finish ]

Factor prints number and its prime factors, each repeated the proper number of times. The number must be positive and less than 254 (about 1.8×1016).

If no number is given, factor reads a stream of numbers from the standard input and factors them. It exits on any input not a positive integer. Maximum running time is proportional to -/n .

Primes prints the prime numbers ranging from start to finish, where start and finish are positive numbers less than 256. If finish is missing, primes prints without end; if start is missing, it reads the starting number from the standard input.