Bash Script to Sort Characters in a String

Use echo "$string" | grep -o . | sort | tr -d '\n' in Bash to sort characters in a string alphabetically.

Examples

Inputstring

Outputginrst

Inputbashscript

Outputabchiprsst

Inputa

Outputa

How to Think About It

To sort characters in a string, first split the string into individual characters, then sort these characters alphabetically, and finally join them back into a single string.

Algorithm

1

Get the input string.

2

Split the string into single characters, one per line.

3

Sort the characters alphabetically.

4

Join the sorted characters back into one string.

5

Print the sorted string.

Code

bash

#!/bin/bash

string="bashscript"
sorted=$(echo "$string" | grep -o . | sort | tr -d '\n')
echo "$sorted"

Output

abchiprsst

Dry Run

Let's trace the string 'bash' through the code

1

Input string

string = 'bash'

2

Split characters

b\na\ns\nh

3

Sort characters

a\nb\ns\nh

4

Join characters

absh

Step	Characters
Split	b,a,s,h
Sort	a,b,s,h
Join	absh

Why This Works

Step 1: Split string into characters

Using grep -o . breaks the string into one character per line.

Step 2: Sort characters

The sort command arranges these characters alphabetically.

Step 3: Join characters back

The tr -d '\n' removes newlines to join characters into a single sorted string.

Alternative Approaches

Using Bash array and sort command

bash

#!/bin/bash
string="bashscript"
arr=($(echo "$string" | fold -w1 | sort))
sorted="${arr[*]}"
sorted=${sorted// /}
echo "$sorted"

This uses an array to hold characters, then joins them after sorting; slightly more complex but clear.

Using pure Bash with parameter expansion and sort

bash

#!/bin/bash
string="bashscript"
sorted=$(printf "%s\n" $(echo "$string" | grep -o .) | sort | tr -d '\n')
echo "$sorted"

Similar to main method but uses printf for splitting; slightly different syntax.

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

Time Complexity

Sorting characters takes O(n log n) time where n is the string length, due to the sorting step.

Space Complexity

Extra space is needed to hold the split characters and the sorted result, so O(n) space.

Which Approach is Fastest?

All approaches rely on sorting, so time complexity is similar; using arrays may add slight overhead but improves readability.

Approach	Time	Space	Best For
grep + sort + tr	O(n log n)	O(n)	Simple and concise scripts
Bash array + sort	O(n log n)	O(n)	Clearer code with arrays
printf + grep + sort	O(n log n)	O(n)	Alternative syntax preference