Loops

Code

#!/bin/bash

# for loop: list
for item in apple banana cherry; do
    echo "Fruit: $item"
done

# for loop: range
for i in {1..5}; do
    echo "Number: $i"
done

# for loop: step
for i in {0..10..2}; do
    echo "Even: $i"
done

# for loop: C-style
for ((i=0; i<5; i++)); do
    echo "Index: $i"
done

# for loop: iterate files
for file in *.txt; do
    echo "Processing: $file"
done

# while loop
count=0
while [ $count -lt 5 ]; do
    echo "Count: $count"
    ((count++))
done

# while read line
while IFS= read -r line; do
    echo "Line: $line"
done < file.txt

# until loop
n=0
until [ $n -ge 5 ]; do
    echo "n=$n"
    ((n++))
done

# break and continue
for i in {1..10}; do
    [ $i -eq 5 ] && break
    [ $((i % 2)) -eq 0 ] && continue
    echo "Odd: $i"
done

# Infinite loop
while true; do
    echo "Running..."
    sleep 1
done

Explanation

Bash supports for/while/until loops, iterating over lists, ranges, files; break/continue control flow.

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