Practice Exercise in Bash Basics Series #5: Using Arrays in Bash

Bash Basics Series
1

If you are following the Bash Basics series on It’s FOSS, you can submit and discuss the answers to the exercise at the end of the chapter:

Fellow experienced members are encouraged to provide their feedback to new members.

Do note that there could be more than one answer to a given problem.

2 
#!/bin/bash

numbers=()

read -p "Enter 3 numbers: " num

IFS=' ' read -r -a numbers <<< "$num"

numbers_length=${#numbers[@]}

reverse_numbers=()

for (( i=$numbers_length-1; i>=0; i-- )); do
        reverse_numbers+=("${numbers[i]}")
done

echo "Numbers in reverse order are: ${reverse_numbers[*]}"
3

I liked the use of IFS. I guess I deliberately omitted that from the tutorial.

1 Like
4

another way to only litmit within the scope of that article, please

5

I still barely understand $IFS - but it gets me every time when I try to use a 2D range of values in a “for loop” - so I then have to “IFS=$'\n” when it gets unhappy :smiley:
$IFS has been tripping (sic) me up for years…

6

My first script for #2 was

#!/bin/bash

echo “Number reversal Exercise”

read -p "enter first number: " num1
read -p "enter second number: " num2
read -p "enter third number: " num3

reverse_number=($num3 $num2 $num1)

echo “The reverse order of numbers entered is ${reverse_number[*]}”

And then I saw the expected output and changed it to

echo “Number reversal Exercise”

echo "Enter three numbers and press enter: "
read -p “–>” num1 num2 num3

reverse=($num3 $num2 $num1)
echo “The reverse order of numbers entered is ${reverse[*]}”

By the way, Thank you Abhishek Prakash for this tutorial, I am learning so much from this.

1 Like