What do you want to achieve?
A transaction often contains a change address. I think disabling this setting does send the remaining coins 'back to the same address' ( means: sending address = change address).
If that's what you want to achieve with the command line, you'll have to built the transaction yourself with the
paytomany command.
In your terminal:
electrum paytomany -F <Your_Sending_Address> -c <Your_Sending_Address> -f <Your_Fee> <Receipent_Address>
Note that you'll have to calculate the output + fee by hand prior executing this command if you are doing it this way.
Your fee simply is
Input - Output(s).
That would be my first approach using the command line.
There is no option to disable change addresses. At least not that i am aware of..
