Manual Pages  — FACTOR

factor – factor a number, generate primes

SYNOPSIS DESCRIPTION DIAGNOSTICS BUGS

factor [-h] [number ...]
primes [-h] [start [stop]]

The factor utility will factor positive integers. When a number is factored, it is printed, followed by a ‘amp;:’, and the list of factors on a single line. Factors are listed in ascending order, and are preceded by a space. If a factor divides a value more than once, it will be printed more than once.

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 0 is entered or an error occurs. Leading white-space and empty lines are ignored.

Numbers may be preceded by a single ‘+’. Numbers can be either decimal or hexadecimal strings where the longest leading substring is used. Numbers are terminated by a non-digit character (such as a newline). If the string contains only decimal digits, it is treated as a decimal representation for a number. A hexadecimal string can contain an optional 0x or 0X prefix. After a number is read, it is factored.

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 the maximum. The default and maximum value of stop is 18446744073709551615.

When the primes utility is invoked with no arguments, start is read from standard input and stop is taken to be the maximum. The start value may be preceded by a single ‘+’. The start value is terminated by a non-digit character (such as a newline).

negative numbers aren't permitted illegal numeric format start value must be less than stop value Result too large

factor cannot handle the "10 most wanted" factor list, primes will not get you a world record.