Connect your keyboard (in my case a logitech K810) to your computer everytime your computer starts. This is a method to be used if when you change OS's often and find that the keyboard has to be re-paired everytime and the pairing process is as cumbersome as the K810.
You should first make sure hidd is installed. Its deprecated but worked best for me. I then checked it with blueman because the default bluetooth manager did not help me at all.
sudo apt-get install bluez-compat blueman
Now place the files as
/etc/init.d/keyboard and make them executable.
sudo chmod +x /etc/init.d/keyboard /etc/keyboard.sh
If you want to connect manually then just;
Thats it. Next time you reboot you should be able to connect the keyboard if the keyboard is in pairing mode.
This script was tested on ubuntu x64 14.04