Sorting an Array in Bash using Insertion Sort

Last Updated : 20 Jul, 2021

Given an array, arr[] of size N, the task is to sort the array in ascending order using Insertion Sort in bash scripting.

Examples:

Input: arr[] = {9, 7, 2, 5}
Output: 2 5 7 9
Explanation: The array in sorted order is {2, 5, 7, 9}

Input: arr[] = {3, 2, 1}
Output: 1 2 3
Explanation: The array in sorted order is {1, 2, 3}

Approach: Follow the steps below to solve the problem:

Traverse the given array, arr[] in the range [1, N] and perform the following steps:
- Compare the current element (key) to its predecessor.
- If the key element is smaller than its predecessor, compare it to the elements before. Move the greater elements one position up to make space for the swapped element.
After completing the above steps, print the sorted array.

Below is the implementation of the above approach:

# Bash program for the above approach
n = 4
arr = (9 7 2 5)

# Perform insertion sort to sort the array
j = 1
while [ $j -lt $n ] 
do
    c = 0
    k = $(expr $j - 1)
    while [ $k -ge 0 ] 
    do
        if [ ${arr[k]} -gt ${arr[j]} ] 
        then
            c=$(expr $c + 1)
        fi
    k = $(expr $k - 1)
    done
    
    x = $j
    y = $(expr $j - 1)
    
    while [ $c -gt 0 ]
    do
        # Swapping the elements
        temp=${arr[x]}
        arr[$x]=${arr[y]}
        arr[$y]=$temp
        
        x=$(expr $x - 1)
        y=$(expr $y - 1)
        c=$(expr $c - 1)
        
    done
    
    j = $(expr $j + 1)
done

# Print the sorted array
echo "${arr[*]}"

Output: