After each update of your UBUNTU #Linux system,in ur Grub menu you can see many versions of kernels..as it may seem odd for you.but actually its showing the ability of a linux system of having multiple kernels.Anyway here i am helping you people those who had felt it as an odd.
Step 1-: First and foremost we need to identify which kernel you are currently running for that issuing of the commands below will help
Then it wil show an output like this
That will be your current kernel which you are using right now.
Step 2-: Next we gonna need the versions of kernels installed on your system for that we need to issue the following command
dpkg -l | grep linux-headers-*
This command will list the installed kernels as in my system it is
Step 3:- Now the final step is to remove the kernels other than the one u got when you had issued the command uname -r.So with apt-get command you gonna attain it.with this command you can remove the respective kernels by specifying the version one by one.
sudo apt-get remove inux-headers-2.6.32-21 linux-headers-18.104.22.168
the version 2.6.32-21 will be removed.
And guys i prefer you please dont remove all the versions of the installed kernels atleast keep a version,so that if your current version get corrupt or fail,It might be useful for you. 🙂