As a logitech fan recently i bought MK330 keyborad combo with m215 mouse.
That usb dongle can support up to 6 devices.The problem is that i still use my old 
K260 (is indestructible keyboard ) and i dont like to have 2 dongles.

Solaar is a Linux tool that allows you to manage Logitech Unifying Receiver mice and keyboards, that comes with both a GUI and command line interface.The application can be used to pair / unpair Logitech devices to the Unifying receiver, it candisplay the battery status for most devices and, for some peripherals, it supports some extra settings that aren't available through the standard Linux system configuration:

• K750 Solar Keyboard: display the current lighting value (Lux);
• K360, MK700, K750 and K800 keyboards: toggle the FN key state;
• Performance MX Mouse: change the DPI;
• M705 Marathon Mouse and M510 Wireless Mouse: toggle smooth scrolling.
  
  

Install

Ubuntu 14.04 or 12.04 / Linux Mint 

sudo add-apt-repository ppa:daniel.pavel/solaar
sudo apt-get update
sudo apt-get install solaar

Ubuntu 14.10 / Linux Mint 17.1 

sudo add-apt-repository ppa:trebelnik-stefina/solaar
sudo apt-get update
sudo apt-get install solaar

Enjoy your logitech and happy typing

Source:webupd8