code: public boolean setEnvironmentVariable(String name, String value)
  			throws SshException {
  		ByteArrayWriter request = new ByteArrayWriter();
  		try {
  			request.writeString(name);
  			request.writeString(value);
  
  			return sendRequest("env", true, request.toByteArray());
  		} catch (IOException ex) {
  			throw new SshException(ex, SshException.INTERNAL_ERROR);
  		} finally {
  			try {
  				request.close();
  			} catch (IOException e) {
  			}
  		}
  	}
docs: The SSH2 session supports the setting of environments variables however
  in our experiance no server to date allows unconditional setting of
  variables. This method should be called before the command is started.