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Landon Curt Noll.
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By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
.Dd January 12, 2020 .Dt FACTOR 6 .Os .Sh NAME .Nm factor , primes .Nd factor a number, generate primes .Sh SYNOPSIS .Nm .Op Fl h .Op Ar number ... .Nm primes .Op Fl h .Op Ar start Op Ar stop .Sh DESCRIPTION The .Nm utility will factor positive integers. When a number is factored, it is printed, followed by a .Ql : , 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.
p When .Nm is invoked with one or more arguments, each argument will be factored.
p When .Nm is invoked with no arguments, .Nm 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.
p Numbers may be preceded by a single .Ql + . 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 .Em 0x or .Em 0X prefix. After a number is read, it is factored.
p The .Nm primes utility prints primes in ascending order, one per line, starting at or above .Ar start and continuing until, but not including .Ar stop . The .Ar start value must be at least 0 and not greater than .Ar stop . The .Ar stop value must not be greater than the maximum. The default and maximum value of .Ar stop is 18446744073709551615.
p When the .Nm primes utility is invoked with no arguments, .Ar start is read from standard input and .Ar stop is taken to be the maximum. The .Ar start value may be preceded by a single .Ql + . The .Ar start value is terminated by a non-digit character (such as a newline). .Sh DIAGNOSTICS l -diag t "negative numbers aren't permitted" t "illegal numeric format" t "start value must be less than stop value" t "Result too large" .El .Sh BUGS .Nm cannot handle the .Dq "10 most wanted" factor list, .Nm primes will not get you a world record.