NAME
          factor, primes - factor a number, generate primes

     SYNOPSIS
          factor [ number ] ...

          primes [ start [ stop ]]

     DESCRIPTION
          The factor utility will factor integers between -2147483648
          and 2147483647 inclusive.  When a number is factored, it is
          printed, followed by a ``:'', 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 error.  Leading white-space and empty lines are
          ignored.  Numbers may be preceded by a single - or +.
          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 255 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 start value is terminated by a non-digit character (such
          as a newline).  The input line must not be longer than 255
          characters.

     DIAGNOSTICS
          Out of range or invalid input results in `ouch' being
          written to standard error.

     BUGS
          Factor cannot handle the ``10 most wanted'' factor list,
          primes won't get you a world record.