Linux Shell Scripting Cookbook - Third Edition

Listing of array indexes

Arrays have indexes for indexing each of the elements. Ordinary and associative arrays differ in terms of index type.

Obtain the list of indexes in an array.

$ echo ${!array_var[*]}

Alternatively, we can also use the following command:

$ echo ${!array_var[@]}

In the previous fruits_value array example, consider the following command:

$ echo ${!fruits_value[*]}
orange apple

This will work for ordinary arrays too.