## table of contents

other sections

FACTOR(1plan9) | FACTOR(1plan9) |

# NAME¶

factor, primes - factor a number, generate large primes# SYNOPSIS¶

**factor**[

*number*]

**primes**[

*start*[

*finish*] ]

# DESCRIPTION¶

*Factor*prints

*number*and its prime factors, each repeated the proper number of times. The number must be positive and less than 2**54 (about 1.8e16) 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 sqrt(n).

*Primes*prints the prime numbers ranging from

*start*to

*finish*, where

*start*and

*finish*are positive numbers less than 2**56. If

*finish*is missing,

*primes*prints without end; if

*start*is missing, it reads the starting number from the standard input.

# SOURCE¶

**/src/cmd/factor.c**

**/src/cmd/primes.c**