**factor**,

**primes**
—

factor a number, generate primes
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.

**factor** cannot handle the “10 most
wanted” factor list;

**primes** won't get you
a world record.