Ltunify
From Gentoo Wiki
Many Logitech input peripherals - mostly mouse and keyboards, but also numpads, presenters, trackballs and touchpads - come with a unique USB receiver. If your peripherals and receiver are not paired from fabric, but support the Logitech Unifying technology, you can still pair them using the app-misc/ltunify package.
The package is available for ~amd64 and ~x86 only.
Installation
Emerge
root #
emerge --ask app-misc/ltunify
Usage
The usage is trivial.
root #
ltunify list
shows the devices actually paired.
root #
ltunify unpair idx
removes a listed paired devices that doesn't exist anymore.
root #
ltunify pair
adds a device simply asking to switch it off and on.
root #
ltunify --help
shows a complete help.