Bash Script to Sort Array in Ascending Order

Use sorted=($(printf "%s\n" "${array[@]}" | sort -n)) to sort a Bash array in ascending order and store the result in a new array.

Examples

Inputarray=(3 1 2)

Outputsorted=(1 2 3)

Inputarray=(10 5 8 1)

Outputsorted=(1 5 8 10)

Inputarray=()

Outputsorted=()

How to Think About It

To sort an array in Bash, print each element on a new line, use the sort -n command to order them numerically, then read the sorted lines back into an array. This uses Bash's ability to handle command substitution and arrays.

Algorithm

1

Take the original array.

2

Print each element on a separate line.

3

Use the <code>sort -n</code> command to sort these lines in ascending numerical order.

4

Capture the sorted output back into a new array.

5

Print or use the sorted array as needed.

Code

bash

array=(3 1 2 10 5)
sorted=($(printf "%s\n" "${array[@]}" | sort -n))
echo "Sorted array: ${sorted[@]}"

Output

Sorted array: 1 2 3 5 10

Dry Run

Let's trace sorting the array (3 1 2 10 5) through the code

1

Original array

array=(3 1 2 10 5)

2

Print elements line by line

3 1 2 10 5

3

Sort output

1 2 3 5 10

4

Read sorted into array

sorted=(1 2 3 5 10)

Step	Array Content
1	3 1 2 10 5
2	3 1 2 10 5
3	1 2 3 5 10
4	1 2 3 5 10

Why This Works

Step 1: Print each element on a new line

Using printf "%s\n" "${array[@]}" sends each array element to a separate line, preparing it for sorting.

Step 2: Sort the lines

The sort -n command sorts the lines numerically in ascending order.

Step 3: Capture sorted output into array

Using sorted=($(...)) reads the sorted lines back into a Bash array for easy use.

Alternative Approaches

Using a for loop with bubble sort

bash

array=(3 1 2 10 5)
for ((i=0; i<${#array[@]}; i++)); do
  for ((j=0; j<${#array[@]}-i-1; j++)); do
    if (( array[j] > array[j+1] )); then
      temp=${array[j]}
      array[j]=${array[j+1]}
      array[j+1]=$temp
    fi
  done
done
echo "Sorted array: ${array[@]}"

This manual sorting is slower and more complex but does not rely on external commands.

Using mapfile and sort

bash

array=(3 1 2 10 5)
mapfile -t sorted < <(printf "%s\n" "${array[@]}" | sort -n)
echo "Sorted array: ${sorted[@]}"

Uses <code>mapfile</code> to read sorted lines into an array, which is cleaner but requires Bash 4+.

Complexity: O(n log n) time, O(n) space

Time Complexity

The sorting uses the external sort command which typically runs in O(n log n) time, where n is the number of elements.

Space Complexity

Extra space is used to hold the printed lines and the sorted array, so space complexity is O(n).

Which Approach is Fastest?

Using the sort command is faster and simpler than manual sorting loops in Bash, especially for larger arrays.

Approach	Time	Space	Best For
Using sort command	O(n log n)	O(n)	Most cases, simple and fast
Manual bubble sort loop	O(n²)	O(1)	Small arrays or no external commands
Using mapfile with sort	O(n log n)	O(n)	Cleaner syntax, Bash 4+ required