NAME
factor —
factor a number
SYNOPSIS
DESCRIPTION
The
factor utility factors integers larger than 1. When a
number is factored, it is printed, followed by a “:”, and the list
of (prime) factors on a single line. Factors are listed in ascending order,
and are preceded by a space. By default, if a factor divides a value more than
once, it will be printed more than once.
When
factor is invoked with one or more
number arguments, each argument will be factored.
When
factor is invoked with no
number
arguments,
factor reads numbers, one per line, from standard
input, until end of file or error. Leading white-space and empty lines are
ignored. Numbers may be preceded by a single +. Integer less than 2 are
rejected. Numbers are terminated by a non-digit character (such as a newline).
After a number is read, it is factored. Input lines must not be longer than
LINE_MAX - 1
(currently 2047) characters.
By default,
factor is compiled against the OpenSSL bignum
implementation
openssl_bn(3), which lets it
handle arbitrarily large values. (Note however that very large values can take
a very long time to factor.) If
factor is compiled without
OpenSSL it is limited to the maximum value of
unsigned
long.
The following option is available:
-
-
- -h
- If the -h flag is specified, factors will
be printed in "human-readable" format. If a factor x divides a
value n (>1) times, it will appear as x^n.
DIAGNOSTICS
Out of range or invalid input results in an appropriate error message to
standard error.
AUTHORS
Originally by
Landon Curt Noll.