Declaring an array
Bash array elements are written inside parentheses with spaces between them. Commas are not required.
sample=("apple" "orange" "grape" "na")Expanding all elements
The notes compare these two forms:
echo "${sample[@]}"
echo "${sample[*]}"With double quotes, ${sample[@]} supplies each element as a separate argument, while ${sample[*]} combines the elements into one argument. Use the [@] form when individual elements must remain distinct.
Finding the array length
echo "${#sample[@]}"The # expansion reports the number of elements.