Let's say you have an array of fruit.

fruit=(banana apple orange grapes)

The += operator can be used to append values to the array. In this example, pineapple is appended to the fruit array.

fruit+=(pineapple)

The array can be printed.

echo $fruit

Echoing the array will show that pineapple has been appended to the array.

banana apple orange grapes pineapple