Question

When trying the execute the following in bash

foo=foo
my_array[$foo]=bar

I get the error ‘bash: foo: expression recursion level exceeded (error token is “foo”)’. But this works fine:

foo=hello
my_array[$foo]=bar

Why is this happening?

Answer 1

The problem is that you are not declaring your array to be associative, so it’s assumed to be a numeric array. When bash tries to evaluate

my_array[$foo]=bar

what he comes into is

my_array[foo]=bar

but the array index ain’t still numeric, so he tries to evaluate it again, leading into

my_array[foo]=bar

as you don’t need to use the $ when in between square brackets. You can see that this goes on and on until a recursion level exceeded exception is thrown.

To solve it, just declare the array as associative:

declare -A my_array