How to Use Array in Bash: Syntax, Examples, and Tips

In Bash, you create an array using array_name=(value1 value2 value3) and access elements with ${array_name[index]}. Arrays start at index 0, and you can get all elements using ${array_name[@]}.

Syntax

To create an array, use parentheses with space-separated values. Access elements by their index inside curly braces with a dollar sign. Indexing starts at 0.

• array_name=(value1 value2 value3): Defines an array with three elements.
• ${array_name[index]}: Accesses the element at the given index.
• ${array_name[@]}: Expands to all elements in the array.

bash

my_array=(apple banana cherry)
echo "First element: ${my_array[0]}"
echo "All elements: ${my_array[@]}"

Output

First element: apple
All elements: apple banana cherry

Example

This example shows how to create an array, print a single element, and loop through all elements to print them one by one.

bash

fruits=(apple banana cherry)
echo "Second fruit: ${fruits[1]}"

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

Output

Second fruit: banana
Fruit: apple
Fruit: banana
Fruit: cherry

Common Pitfalls

Common mistakes include forgetting quotes around ${array[@]} in loops, which can cause word splitting issues, and using parentheses instead of square brackets for indexing.

Also, arrays must be declared with parentheses; using spaces without parentheses creates separate variables.

bash

# Wrong: missing quotes causes word splitting
fruits=(apple banana cherry)
for fruit in ${fruits[@]}; do
  echo "$fruit"
done

# Right: quotes preserve each element
for fruit in "${fruits[@]}"; do
  echo "$fruit"
done

Output

apple
banana
cherry
apple
banana
cherry

Quick Reference

Command	Description
array=(val1 val2 val3)	Create an array with values
${array[0]}	Access first element
${array[@]}	Access all elements
${#array[@]}	Get number of elements
array+=(val4)	Add element to array
unset array[index]	Remove element at index

Key Takeaways

Create arrays with parentheses and space-separated values.

Access elements using ${array[index]}, starting at zero.

Use "${array[@]}" with quotes to safely loop over all elements.

Get array length with ${#array[@]}.

Add elements using += and remove with unset.