Bash Arrays

Description

In Bash, an array is a collection of elements that act as variables. They have a ton of uses and this article will go over some of the basics when it comes to using arrays and elements in your Bash scripts.

Defining an Array

Array of string values

array=("pineapple" "blueberry" "mango" "kiwi" "dragonfruit")

Array of integers

integers=(2 9 3 11 8)

Calling an Array

Call an entire array

echo "I enjoy eating ${array[@]}"

Result: I enjoy eating pineapple blueberry mango kiwi dragonfruit

Call a specific array element

Example 1

echo "I enjoy eating ${array[3]}"

Result: I enjoy eating kiwi

Example 2

echo "I enjoy eating ${array[0]}"

Result: I enjoy eating pineapple

Array Iteration

Iterate through an array using a for loop

for fruit in ${array[@]}; do
  echo "I enjoy eating $fruit"
done

Result:

I enjoy eating pineapple
I enjoy eating blueberry
I enjoy eating mango
I enjoy eating kiwi
I enjoy eating dragonfruit

Counting Array Elements

echo "There are ${#array[@]} elements in the array"

Result: There are 5 elements in the array

Sorting Array Elements

# Define an array of integers
integers=(2 9 3 11 8)

#Sort array
sorted_numbers=($(echo "${integers[@]}" | tr ' ' '\n' | sort -n))

#Print the result
echo ${sorted_numbers[@]}

Result: 2 3 8 9 11

Concatenating Arrays

# Define two arrays of strings
colors=("red" "green" "blue")
more_colors=("orange" "purple")

# Concatenate the two arrays 
combined=("${colors[@]}" "${more_colors[@]}")

# Print the result
echo "Combined colors: ${combined[@]}"

Result: Combined colors: red green blue orange purple

Slice an Array

# Define an array of integers
integers=(2 9 3 11 8)

# Slice the array to create a new array with elements 3 through 7
sliced_integers=("${integers[@]:2:5}")

# Print the result
echo "Sliced integers: ${sliced_integers[@]}"

Result: Sliced integers: 3 11 8

Search for an element in an array

Multidimensional arrays

Associative arrays