## NAME

`factor`

, `primes`

— factor a number, generate
primes

## SYNOPSIS

`factor` |
[number ...] |

`primes` |
[start [stop]] |

## DESCRIPTION

The `factor`

utility will factor 64-bit
positive integers. When a number is factored, it is printed, followed by a
‘:’, and the list of its prime factors in ascending order, on
a single line. Every prime factor is printed as often as it divides the
number.

When `factor`

is invoked with one or more
arguments, each argument will be factored.

When `factor`

is invoked with no arguments,
`factor`

reads numbers, one per line, from standard
input, until end of file or error. White-space and empty lines are ignored.
Numbers may be preceded by a single +. After a number is read, it is
factored. Input lines must not be longer than 99 characters.

The `primes`

utility prints primes in
ascending order, one per line, starting at or above
`start` and continuing until, but not including
`stop`. The `start` value must be at
least 0 and not greater than `stop`. The
`stop` value must not be greater than 4294967295. The
default value of `stop` is 4294967295.

When the `primes`

utility is invoked with no
arguments, `start` is read from standard input.
`stop` is taken to be 4294967295. The
`start` value may be preceded by a single +. The input
line must not be longer than 99 characters.

## BUGS

`factor`

cannot handle the “10 most
wanted” factor list; `primes`

won't get you a
world record.