Array Sorting (The GNU Awk User’s Guide)

From Get docs

12.2 Controlling Array Traversal and Array Sorting

gawk lets you control the order in which a ‘for (indx in array)’ loop traverses an array.

In addition, two built-in functions, asort() and asorti(), let you sort arrays based on the array values and indices, respectively. These two functions also provide control over the sorting criteria used to order the elements during sorting.

Controlling Array Traversal    How to use PROCINFO["sorted_in"].
Array Sorting Functions    How to use asort() and asorti().