I am attempting to follow the instructions for opening an alternative wallet in an existing Electrum installation on a Mac in OSX - 10.6.8 and running the last stable version of Electrum 1.9.4 for that OS version.  I am using the Apple terminal to start Electrum and trying to point it to a wallet file on another volume, but I get the response that "-w" is an "invalid option".  Electrum does start from the terminal using  -a Electrum but from there I can't seem to connect with the path to the wallet.  Any suggestions much appreciated.