Prime Number in Bash

Welcome to the Prime Number in Bash page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

#!/bin/bash

ERROR="Usage: please input a non-negative integer"

# based on https://stackoverflow.com/questions/45392068/check-if-a-number-is-a-prime-in-bash
function is_prime(){
    if [[ $1 -eq 2 ]] || [[ $1 -eq 3 ]]; then
        return 1  # prime
    fi
    if [[ $(($1 % 2)) -eq 0 ]] || [[ $(($1 % 3)) -eq 0 ]] || [[ $1 -eq 1 ]]; then
        return 0  # not a prime
    fi
    i=5; w=2
    while [[ $((i * i)) -le $1 ]]; do
        if [[ $(($1 % i)) -eq 0 ]]; then
            return 0  # not a prime
        fi
        i=$((i + w))
        w=$((6 - w))
    done
    return 1  # prime
}

# validate input number
if [[ -z "${1}" ]]
then
	echo "${ERROR}"
	exit 1
fi

if ! [[ "${1}" =~ ^[0-9]+$ ]]
then
  echo "${ERROR}"
  exit 1
fi

# sample usage
is_prime ${1}
if [[ $? -eq 0 ]];
then
  echo "composite"
else
  echo "prime"
fi

exit 0

Prime Number in Bash was written by:

• Jeremy Grifski
• thetbl

If you see anything you'd like to change or update, please consider contributing.

Note: The solution shown above is the current solution in the Sample Programs repository as of May 22 2021 15:02:49. The solution was first committed on Oct 14 2019 21:17:21. As a result, documentation below may be outdated.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.