Bash For Loop Examples
Bash For Loop Examples

If you are new to Bash scripting or Linux shell scripting, one of the most useful concepts you need to learn is the Bash for loop. A for loop allows you to run a command multiple times without writing it repeatedly. This makes tasks like file processing, renaming, or printing numbers much easier and faster.

In this guide, we will cover all the important types of Bash for loops with simple explanations and practical examples.

What is a Bash For Loop?

A for loop in Bash is a way to repeat commands for each item in a list. Instead of typing the same command over and over, the loop handles it for you.

Basic Syntax of a For Loop in Bash

for item in list
do
   command to run
done
  • item → a variable that changes with each step of the loop
  • list → the values the loop goes through (words, numbers, files, or array items)

Bash For Loop with Words (Beginner Example)

for fruit in apple banana cherry
do
  echo "I like $fruit"
done

Output:

I like apple
I like banana
I like cherry

This loop goes through each word and prints it.

Loop Through Numbers

The most common use of a for loop in Bash is to work with numbers.

for i in {1..5}
do
  echo "Number $i"
done

Output:

Number 1
Number 2
Number 3
Number 4
Number 5

Loop With Step Values

You can also skip numbers by using steps.

for i in {0..10..2}
do
  echo "Even number: $i"
done

Output:

Even number: 0
Even number: 2
Even number: 4
Even number: 6
Even number: 8
Even number: 10

Bash For Loop to Process Files

A very useful case in Linux shell scripting is looping through files.

for file in *.txt
do
  echo "Found file: $file"
done

Output (if files exist):

Found file: notes.txt
Found file: data.txt
Found file: report.txt

Loop Through Array Items

colors=("red" "green" "blue")
for c in "${colors[@]}"
do
  echo "Color: $c"
done

Output:

Color: red
Color: green
Color: blue

C-Style Bash For Loop

If you have experience with languages like C or Java, this style will look familiar.

for ((i=1; i<=5; i++))
do
  echo "Count: $i"
done

Output:

Count: 1
Count: 2
Count: 3
Count: 4
Count: 5

Using Break and Continue

You can control loops using break and continue.

for i in {1..5}
do
  if [ $i -eq 3 ]; then
    continue
  fi
  if [ $i -eq 5 ]; then
    break
  fi
  echo "Value: $i"
done

Output:

Value: 1
Value: 2
Value: 4

Explanation:

  • Skips number 3 because of continue
  • Stops the loop completely at 5 because of break

Nested For Loops Example

You can put one loop inside another to combine values.

for i in 1 2
do
  for j in A B
  do
    echo "$i$j"
  done
done

Output:

1A
1B
2A
2B

Real-Life Example: Rename Files

for file in *.jpg
do
  mv "$file" "backup_$file"
done

If you have files like image1.jpg and image2.jpg, after running the loop they become:

backup_image1.jpg
backup_image2.jpg

Conclusion:

Learning this concept is essential for anyone who wants to get better at Linux shell scripting.

  • It saves time by automating repetitive tasks.
  • It works with numbers, words, arrays, and files.
  • It can be controlled with break and continue.
  • It is powerful enough for real-life tasks like file processing and automation.

Mastering Bash scripting for beginners often starts with understanding loops. Once you are comfortable with for loops, you can easily move on to more advanced Bash scripting concepts.

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