10_primes.sh

#!/bin/bash
# Print (to stdout) all prime numbers between 60000 and 63000. The output should be nicely formatted in columns.

print_prime_numbers()
{
    local START_NUM=$1
    local END_NUM=$2
    local count=1

    while [[ $START_NUM -le $END_NUM ]]
    do
        number=$START_NUM
        prime=true
        i=2

        # We don't need go through every number. SQRT of $number is enough.
        #+(For Bash, I made some modifications by changing SQRT of "$number" to square number of $i.
        #+So now there is no need for external function)
        while [[ $(( i * i )) -lt $(( number - 1 )) ]]
        do
            if [[ $(( number % i )) -eq 0 ]]
            then
                prime=false
                break
            fi
            let i++
        done

        if [[ "$prime" = true ]]
        then
            printf "%d " $number
            let count++
        fi

        [[ $count -eq 13 ]] && count=1 && echo

        let START_NUM++
    done
}

print_prime_numbers 60000 63000

exit 0