factor command in Linux with examples

The factor command in Linux is used to print the prime factors of the given numbers, either given from the command line or read from standard input. The numbers given through standard input may be delimited by tabs, spaces or newlines.

Syntax

factor [NUMBER]

You can provide one or more numbers as arguments. If no numbers are provided, the command reads from standard input.

Examples of Using the factor Command

1. Prime Factorization of a Non-Prime Number

Let’s say you want to find the prime factors of 100. The number 100 is composite made up of the prime factors 2 and 5:

This output shows that 100 is composed of two 2s and two 5s.

2. Prime Factorization of a Prime Number

If you input a prime number, the factor command will return the number itself. For example, 13 is a prime number:This output indicates that 13 is prime and cannot be factored further.

3. Factorization of a Product of Two Primes

The factor command can also handle numbers that are the product of two primes. For instance, 221 is the product of 13 and 17:

Under the hood, the factor command uses the Pollard-Brent rho algorithm to find out the prime factors.

4. factor --help

This command only supports a few numbers of options, that is its help command and version number.

Conclusion

The factor command, with its simple syntax and ability to handle both single and multiple numbers, is an essential tool for prime factorization on Linux. If you're working on mathematical computations, cryptography, or simply need to factor numbers, factor provides a quick and efficient way to get the job done and a valuable addition to any Linux user’s toolkit.