NAME

factor — ise integers

SYNOPSIS

DESCRIPTION

Writes factors of all numbers (if none specified, read from standard input, delimited by whitespace) to the standard output stream in ascending order, one per line, in the form

No primes are written for numbers smaller than 2.

EXIT STATUS

1 if at least one number wasn't actually, or was out of range.

EXAMPLES

$ factor 1410 1981
1410: 2 3 5 47
1981: 7 283

$ tr -cd '0-9 \t\n' < /dev/urandom | dd bs=60 count=1 | factor
11: 11
41615: 5 7 29 41
0:
81: 3 3 3 3
1:
552: 2 2 2 3 23
7: 7
4900: 2 2 5 5 7 7
195283: 11 41 433
440343080901: 3 3 29 53 31832797
7472183475: 3 5 5 99629113

HISTORY

factor first appeared in Version 7 AT&T UNIX as factor(1):

A direct C port appeared in 4.1BSD as factor(6). It had been rewritten in 4.3BSD-Reno to parse one number per line, as opposed to just separating them by whitespace, and handle multiple arguments.

BUGS

This implementation uses a simplistic wheel factorisation algorithm, which isn't going to win any awards soon.