[Ethereum] geth attach not working on osx, problem with geth.ipc

I don't have a complete answer, but I believe it has to do with the console's automatic resolution of javascript promises. For example,

Contract.deployed().then(instance => instance.contract)

the truffle console will actually wait for the final .then promise to resolve and will then print instance.contract. That said, I would imagine that

new Promise(() => console.log('test'))

would work, or even

new Promise(() => 'test')

but they don't for me. I don't know enough about promises or the truffle console to understand why that doesn't work. Hopefully this gets fixed in the future. For now, you can do

Contract.deployed().then(() => console.log('test'))

or

Contract.deployed().then(() => 'test')

as workarounds.

It sounds like the socket is not connected to your geth instance. I saw here that geth.ipc could cause problems, you can try:

rm -f /home/my_local_username/.ethereum/testnet/geth.ipc

I don't see the bug myself but this socket stays when hard killing geth and could be in a bad state for you. You should also check the logs on starting geth to see if any socket warnings or errors are raised.