Iterating Over Data in Bash Scripts

Discover diverse examples of for loops in Bash scripts, showcasing different techniques for iterating over data. From numeric ranges to arrays, file contents, command output, and glob patterns, these examples demonstrate the versatility of for loops in processing data efficiently.

Whether you're automating tasks or enhancing script functionality, these examples offer valuable insights for leveraging for loops effectively in your Bash scripts.

For sample

for i in $( whoami ); do
    echo item: $i
done

Numeric Range

for i in {1..10}; do
    # Loop body
    echo $i
done

C-Style Loop

for ((i=1; i<=10; i++)); do
    # Loop body
    echo $i
done

Iterating over an Array

my_array=("apple" "banana" "orange")

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

Reading Lines from a File

while IFS= read -r line; do
    echo $line
done < input.txt

Command Output

for file in $(ls); do
    echo $file
done

Glob Pattern Matching

for file in *.txt; do
    echo $file
done

Arithmetic Progression

for ((i=0; i<=10; i+=2)); do
    # Loop body
    echo $i
done

Print cpu temperature by a simple for loop

for d in /sys/class/hwmon/hwmon*; do
  name=$(cat "$d/name" 2>/dev/null)
  for t in "$d"/temp*_input; do
    [ -e "$t" ] || continue
    label="${t%_input}_label"
    printf "%s | %s | %.1f°C\n" \
      "$name" \
      "$(cat "$label" 2>/dev/null || echo $(basename "$t"))" \
      "$(awk '{print $1/1000}' "$t")"
  done
done