Linux old kernels clean up helper

remove_kernel.sh

# function to remove packages related to kernel version
function remove_kernel {
    sudo dpkg --purge  linux-headers-$1-generic;
    sudo dpkg --purge  linux-headers-$1;
    sudo dpkg --purge  linux-image-$1-generic;
}
 
function list_old_kernels {
    for kname in $(dpkg -l "linux-[hi][em]*[0-9]\.[0-9]\.[0-9]-*" | awk '{print $1 " " $2}' | grep -v -e "^un*" | grep -Po "([0-9]+\.[0-9]+\.[0-9]+\-[0-9]+)" | sort -u --version-sort); do
        if [ "$kname" == $(uname -r | grep -Po "([0-9]+\.[0-9]+\.[0-9]+\-[0-9]+)") ]; then
            # skip currently used kernel and all folowing
            break;
        fi
        echo "$kname";
    done
}

function remove_all_old_kernels {
    for kversion in $(list_old_kernels); do
        remove_kernel "$kversion";
    done
} 

# remove kernel version
#    remove_kernel <version>
#    remove_kernel <3.2.0-68>

# or to remove all old kernels, use this command
#    remove_all_old_kernels