cmd(options)
Instance Public methods
Send a command to the host.
More exactly, sends a string to the host, and reads in all received data
until is sees the prompt or other matched sequence.
If a block is given, the received data will be yielded to it as it is read
in. Whether a block is given or not, the received data will be return as a
string. Note that the received data includes the prompt and in most cases
the host's echo of our command.
options is either a String, specified