Sort an associative array in awk

Instead of asort, use asorti(source, destination) which sorts the indices into a new array and you won’t have to copy the array.

Then you can use the destination array as pointers into the source array.

For your example, you would use it like this:

n=asorti(chr_count, sorted)
for (i=1; i<=n; i++) {
        print sorted[i] " : " chr_count[sorted[i]]
}