A prime number is a whole number that has exactly 2 different factors, 1 and itself. A number that is not a prime number will be called composite. Except 1 each natural number that is divisible by only 1 and itself is called a prime number. For example: 2,3,5,7,11,13,17,19,23,29… etc.

- There are total 25 prime number upto 100 and 46 prime numbers upto 200.
- 2 is the only prime number and the smallest prime number, rest all prime numbers are odd.
- 1 is neither prime not composite number.

## Bash Script to Find Prime number is a given Range of Numbers

1. Configure the script as shown below in /tmp/prime_num.sh file:

#!/bin/bash prime_1=0 echo "enter the range" read n echo " Prime number between 1 to $n is:" echo "1" echo "2" for((i=3;i<=n;)) do for((j=i-1;j>=2;)) do if [ `expr $i % $j` -ne 0 ] ; then prime_1=1 else prime_1=0 break fi j=`expr $j - 1` done if [ $prime_1 -eq 1 ] ; then echo $i fi i=`expr $i + 1` done

2. Assign executible permissions to the file before running it:

$ chmod +x /tmp/prime_num.sh

3. Run the script as shown below and provide a range (for example 50 to find prime numbers between 0 to 50).