# factor(1) [plan9 man page]

FACTOR(1) General Commands Manual FACTOR(1)NAME

factor, primes - factor a number, generate large primesSYNOPSIS

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**56 (about 7.2e16) 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

/sys/src/cmd/factor.c /sys/src/cmd/primes.c FACTOR(1)

## Check Out this Related Man Page

factor(1) General Commands Manual factor(1)NAME

factor, primes - factor a number, generate large primesSYNOPSIS

[number] [start[stop]]DESCRIPTION

If no arguments are provided on the command line, waits for a number to be typed in. If a positive number is typed, it factors the number and print its prime factors; each one is printed the proper number of times. It then waits for another number. exits if it encounters a zero or any non-numeric character. If an argument is provided on the command line, factors the number as above, then exits. Maximum time to factor is proportional to sqrt(n) and occurs when n is prime or the square of a prime. The largest number that can be dealt with by is 1.0e14. prints prime numbers between a lower and upper bound. If no arguments are provided on the command line, waits for two numbers to be typed in. The first number is interpreted as the lower bound; the second as the upper bound. All prime numbers in the resulting inclusive range are printed. If start is specified, all primes greater than or equal to start are printed. If both start and stop are given, all primes occurring in the inclusive range start through stop are printed. start and stop values must be integers represented as long integers. If the stop value is omitted in either case, runs either until overflow occurs or until it is stopped by typing the interrupt character. The largest number that can be dealt with by is 2,147,483,647.DIAGNOSTICS

Both commands print when the input is out of range, illegal characters are encountered, or when start is greater than stop.EXAMPLES

Print the prime factorization for the number 12: Print all prime numbers between 0 and 20: factor(1)