Question

⦁   Write a Bash script that prompts for user input and reads a string of text from the user. If the user enters a no null (no empty) string, the script should prompt the user to re-enter again the string; otherwise should display the string entered “.

⦁   Given an array of the following four integers (3, 5, 13, 14); write a Bash script to display the second and all elements in the array.

  

⦁   Write a short Bas script to display even numbers in a set of 13 to 21 using a WHILE loop technique.

⦁   Re-write your WHILE loop script in previous question using a FOR loop for the same set of numbers of 13 to 21.

Answer 1

1. Write a Bash script that prompts for user input and reads a string of text from the user. If the user enters a no null (no empty) string, the script should prompt the user to re-enter again the string; otherwise should display the string entered “.

Solution

#!/bin/bash    

# Read the user input     

echo "Enter a string: "  

read input_string

if [ input_string == ' ' ];  

then    

  echo "Enter a not null string: "  

  read input_string

else  

   echo "$input_string"  

fi  

2. Given an array of the following four integers (3, 5, 13, 14); write a Bash script to display the second and all elements in the array.

#!/bin/bash  
#Script to print an element of an array with an index of 2 and all elements of array 
  
#declaring the array  
declare -a example_array=( 3 5 13 14  )  
  
#printing the element with index of 2  
echo ${example_array[2]}  
#output is 13

#Printing all the elements  
echo "${example_array[@]}" 
#output is 3 5 13 14

3.Write a short Bas script to display even numbers in a set of 13 to 21 using a WHILE loop technique.

#!/bin/bash  
#While Loop  
  
i=13 
while [ $i -le 21 ]  
do  
rm = $i%=2; 
((i++))
if [[ "$rm" == 0 ]];  
then  
    echo "This is an even Number : $i"  
else
 continue
fi  

done  

4.  Re-write your WHILE loop script in previous question using a FOR loop for the same set of numbers of 13 to 21.

#!/bin/bash  
#for Loop 

for num in {13..21}  
do  
  rm = $num%=2; 
  if [[ "$rm" == 0 ]];  
  then  
    echo "This is an even Number : $i"  
  fi 
done

Hope it will help you, have a great day!!!...

Thank you.