factor(6) - NetBSD Manual Pages

FACTOR(6)                     NetBSD Games Manual                    FACTOR(6)


NAME

     factor -- factor a number


SYNOPSIS

     factor [-hx] [number ...]


DESCRIPTION

     The factor utility factors integers larger than 0.  When a number is fac-
     tored, it is printed, followed by a ``:'', and the list of (prime) fac-
     tors 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 +.  Numbers that start with 0x are interpreted as hexadecimal.  A
     0 input exits the program.  Negative numbers are not allowed.  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.

     -x    If the -x flag is specified, factors will be printed in hexadecimal
           format.


DIAGNOSTICS

     Out of range or invalid input results in an appropriate error message to
     standard error.


AUTHORS

     Originally by Landon Curt Noll.

NetBSD 10.99                   October 12, 2020                   NetBSD 10.99