addnode in bitcoin.conf doesn't work (Regtest mode) I'm trying to make to nodes on the same computer communicate. 
I set up two bitcoin folder with two bitcoin.conf files.
bitcoin.conf in the second node is the following:

rpcuser=bitcoinrpc 
rpcpassword=roiroiroiroiroi
addnode=127.0.0.1:18444


while in the first node is just I've just set the rpcuser and rpcpasswords

Now I start the nodes with the following command

First node
./bitcoin/src/bitcoind -regtest

Second node ./bitcoin/src/bitcoind  -regtest -rpcport=5444 -port=18888 -datadir=/Users/tommaso/.bitcoin/ 

But they don't connect to each other.

Only if a run the command ./bitcoin/src/bitcoin-cli  -regtest -rpcport=5444 -datadir=/Users/tommaso/.bitcoin/ addnode "127.0.0.1:18444" "onetry"
 they finally connect

Why does addnode=127.0.0.1:18444 in bitcoin.conf doesn't work?
well im late but i can tell.

it works, use following string

addnode IP:8333 add   but the Port you dont need to show, because everyone uses the same port, because thats the one he set as open on his router. the rpc port must only defined once at startupt. in addnode dont use it, because you could be bound on an IP too via the bind= command, then the server dont know what to do.