associative arrays' ".keys()"

Question

In Bash (v4+):

$ declare -A x=([foo]=bar [coconut]=banana)
$ echo ${x[@]}

gives:

banana bar

What can I type to get this:

foo coconut

Answer 1

You can preceed x in echo ${x[@]} with a ! to get keys:

echo ${!x[@]}

More information on associative arrays: http://www.artificialworlds.net/blog/2012/10/17/bash-associative-array-examples/