---
name: "factor"
section: "6"
platform: "linux"
package: "bsdgames"
version: "1.3-7"
release: "Debian 1.3 (Bo)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/factor/6"
---

# factor(6)

factor a number, generate primes

## 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.