Loops are one of the most important concepts in Shell Scripting. They allow us to execute a block of code repeatedly until a specific condition is met.

In this article, we'll explore for loops and while loops with beginner-friendly examples.

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1️⃣ Creating Multiple Files Using a for Loop

This script creates multiple files based on a given range.

Script

#!/bin/bash

# 1 -> Folder/File name
# 2 -> Start range
# 3 -> End range

for (( num=\(2; num<=\)3; num++ ))
do
    touch "\(1\)num"
done

Explanation

• $1 → File name prefix

• $2 → Starting number

• $3 → Ending number

• touch → Creates an empty file

• num++ → Increments the value by 1

Example

bash create_files.sh file 1 5

Output

file1
file2
file3
file4
file5

This script is useful when creating multiple files automatically instead of manually creating them one by one.

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2️⃣ Creating Files Using User Input

Instead of passing arguments from the command line, we can ask the user for inputs.

Script

#!/bin/bash

read -p "Enter the file name prefix: " fol
read -p "Enter start range: " start
read -p "Enter end range: " end

for (( num=\(start; num<=\)end; num++ ))
do
    touch "\(fol\)num"
done

Example Run

Enter the file name prefix: test
Enter start range: 1
Enter end range: 5

Output

test1
test2
test3
test4
test5

Concepts Used

• read -p → Takes user input

• for loop → Iterates through a range

• touch → Creates files

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3️⃣ Printing Even Numbers Using a while Loop

A while loop executes repeatedly as long as the condition remains true.

Script

#!/bin/bash

num=0

while (( num <= 10 && num % 2 == 0 ))
do
    echo $num
    ((num+=2))
done

Output

0
2
4
6
8
10

Explanation

• num=0 initializes the variable.

• num <= 10 ensures numbers are printed up to 10.

• num % 2 == 0 checks whether the number is even.

• ((num+=2)) increments by 2 to get the next even number.

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4️⃣ Printing Odd Numbers Using a while Loop

Script

#!/bin/bash

num=1

while (( num <= 10 && num%2 != 0))
do
    echo $num
    ((num+=2))
done

Output

1
3
5
7
9

Explanation

Since the loop starts with 1 and increments by 2, only odd numbers are printed.

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Key Takeaways

✅ for loops are best when the number of iterations is known.

✅ while loops are useful when execution depends on a condition.

✅ touch can automate file creation tasks.

✅ Arithmetic operations in shell scripting use (( )).

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Conclusion

Loops are a fundamental part of Linux Shell Scripting and are widely used in automation, DevOps tasks, system administration, and server management. Mastering for and while loops helps you write efficient scripts, reduce repetitive work, and automate everyday Linux operations.

Start practicing these examples and gradually combine loops with conditions, functions, and file operations to build powerful shell scripts. 🚀

Happy Scripting! 🐧💻