Bash — For Loops

Basic for loop

#!/bin/bash

for i in 1 2 3 4 5; do
    echo "$i"
done

Range

#!/bin/bash

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

# With step
for i in {1..10..2}; do
    echo "$i"  # 1 3 5 7 9
done

C-style for loop

#!/bin/bash

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

Iterating files

#!/bin/bash

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

# With path
for file in /path/to/*.log; do
    echo "Log: $file"
done

Iterating arrays

#!/bin/bash

fruits=("Apple" "Banana" "Cherry")

for fruit in "${fruits[@]}"; do
    echo "$fruit"
done

# With index
for i in "${!fruits[@]}"; do
    echo "$i: ${fruits[$i]}"
done

Word splitting

#!/bin/bash

for word in This is a sentence; do
    echo "$word"
done

Mini Practice

Write Bash code that:

1. Uses a range-based for loop
2. Iterates over files with a glob
3. Iterates over an array
4. Uses a C-style for loop

Up Next

In the next lesson, you'll learn about While Loops — while and until loops.