How to Write a for Loop in Bash in 2025?

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by admin , in category: Q&A , 2 days ago

Bash scripting remains a fundamental skill for developers and IT professionals alike, even as we step into 2025. One of the most essential constructs in bash scripting is the for loop, which allows you to iterate over a list of items efficiently. Understanding how to leverage for loops can dramatically streamline your scripts, making them more efficient and effective.

Basics of a For Loop in Bash

A for loop in bash is used to execute a sequence of commands multiple times. It iterates over a list of items, executing the specified commands for each item. Here’s a simple example:

#!/bin/bash

# Declare a list of items
items=("apple" "banana" "cherry")

# Iterate over each item
for item in "${items[@]}"
do
  echo "I love $item!"
done

Explanation

Initialization: The items array is initialized with three elements: “apple”, “banana”, and “cherry”.
Iteration: The for loop assigns each item in the items array to the variable item and then executes the block of commands within do...done.

Advanced For Loop Techniques

In 2025, bash scripting includes enhancements that allow for advanced looping techniques, making scripts even more powerful. Consider the following:

C-Style For Loops: You can now write C-like for loops in bash to iterate using initialization, condition, and increment expressions.

   for (( i=0; i<5; i++ ))
   do
     echo "Iteration $i"
   done

Reading File Lines: Efficiently read and process file lines using a for loop and read command:

1
2
3

   while IFS= read -r line; do
     echo "Processing line: $line"
   done < "filename.txt"

Conclusion

Mastering for loops in bash is an invaluable skill in 2025. Whether you are processing files or automating tasks, understanding how to implement efficient loops will enhance your scripts. For further reading, check out these related articles: