Kernels updating

You can find out what kernel you are currently using with the uname command:

uname -r


Show installed but unused linux headers, image, or modules:

dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'