我对此有很多疑问：
Desinstalando linux-image-extra-4.8.0-54-generic (4.8.0-54.57~16.04.1) ...
depmod: FATAL: could not load /boot/System.map-4.8.0-54-generic: No such file or directory
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.8.0-54-generic /boot/vmlinuz-4.8.0-54-generic
run-parts: executing /etc/kernel/postinst.d/dkms 4.8.0-54-generic /boot/vmlinuz-4.8.0-54-generic
Error! Your kernel headers for kernel 4.8.0-54-generic cannot be found.
Please install the linux-headers-4.8.0-54-generic package,
or use the --kernelsourcedir option to tell DKMS where it's located
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.8.0-54-generic /boot/vmlinuz-4.8.0-54-generic
update-initramfs: Generating /boot/initrd.img-4.8.0-54-generic
WARNING: missing /lib/modules/4.8.0-54-generic
Ensure all necessary drivers are built into the linux image!
depmod: ERROR: could not open directory /lib/modules/4.8.0-54-generic: No such file or directory
depmod: FATAL: could not search modules: No such file or directory
cp: se omite el directorio '/etc/udev/rules.d/90-extraacl.rules'
E: /usr/share/initramfs-tools/hooks/udev failed with return 1.
update-initramfs: failed for /boot/initrd.img-4.8.0-54-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error al procesar el paquete linux-image-extra-4.8.0-54-generic (--remove):
el subproceso instalado el script post-removal devolvió el código de salida de error 1
Desinstalando linux-image-extra-4.8.0-56-generic (4.8.0-56.61~16.04.1) ...
depmod: FATAL: could not load /boot/System.map-4.8.0-56-generic: No such file or directory
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.8.0-56-generic /boot/vmlinuz-4.8.0-56-generic
run-parts: executing /etc/kernel/postinst.d/dkms 4.8.0-56-generic /boot/vmlinuz-4.8.0-56-generic
Error! Your kernel headers for kernel 4.8.0-56-generic cannot be found.
Please install the linux-headers-4.8.0-56-generic package,
or use the --kernelsourcedir option to tell DKMS where it's located
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.8.0-56-generic /boot/vmlinuz-4.8.0-56-generic
update-initramfs: Generating /boot/initrd.img-4.8.0-56-generic
WARNING: missing /lib/modules/4.8.0-56-generic
Ensure all necessary drivers are built into the linux image!
depmod: ERROR: could not open directory /lib/modules/4.8.0-56-generic: No such file or directory
depmod: FATAL: could not search modules: No such file or directory
cp: se omite el directorio '/etc/udev/rules.d/90-extraacl.rules'
E: /usr/share/initramfs-tools/hooks/udev failed with return 1.
update-initramfs: failed for /boot/initrd.img-4.8.0-56-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error al procesar el paquete linux-image-extra-4.8.0-56-generic (--remove):
el subproceso instalado el script post-removal devolvió el código de salida de error 1
Desinstalando linux-image-extra-4.8.0-58-generic (4.8.0-58.63~16.04.1) ...
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.8.0-58-generic /boot/vmlinuz-4.8.0-58-generic
run-parts: executing /etc/kernel/postinst.d/dkms 4.8.0-58-generic /boot/vmlinuz-4.8.0-58-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.8.0-58-generic /boot/vmlinuz-4.8.0-58-generic
update-initramfs: Generating /boot/initrd.img-4.8.0-58-generic
cp: se omite el directorio '/etc/udev/rules.d/90-extraacl.rules'
E: /usr/share/initramfs-tools/hooks/udev failed with return 1.
update-initramfs: failed for /boot/initrd.img-4.8.0-58-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error al procesar el paquete linux-image-extra-4.8.0-58-generic (--remove):
el subproceso instalado el script post-removal devolvió el código de salida de error 1
Se encontraron errores al procesar:
linux-image-extra-4.8.0-54-generic
linux-image-extra-4.8.0-56-generic
linux-image-extra-4.8.0-58-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)