Bitcoind daemon: error connecting to the server?

I am trying to create a new bitcoin address and store it in a shell variable $NEW_ADDRESS.

When I run this command:

$NEW_ADDRESS=$(./bitcoin-cli getnewaddress)

I get the following errors:

error: Could not connect to the server 127.0.0.1:8332
Make sure the bitcoind server is running and that you are connecting to the correct RPC port.
-bash: =: command not found

I have tried everything to fix the connection error, including typing the command:

./bitcoind -rpcport=8332

Or even, changing the bitcoin config:

nano ~/.bitcoin/bitcoin.conf

And typing these lines on the configuration:

rpcconnect=127.0.0.1
rpcport=8332;

But nothing works. Does anyone have an idea on how to troubleshoot and fix this?

Thanks in advance.