dilanka@android:~/Downloads$ dpkg -P linux-image-extra-4.4.0-87-generic
dpkg: error: requested operation requires superuser privilege
dilanka@android:~/Downloads$ sudo dpkg -P linux-image-extra-4.4.0-87-generic
(Reading database ... 484606 files and directories currently installed.)
Removing linux-image-extra-4.4.0-87-generic (4.4.0-87.110~14.04.1) ...
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.4.0-87-generic /boot/vmlinuz-4.4.0-87-generic
run-parts: executing /etc/kernel/postinst.d/dkms 4.4.0-87-generic /boot/vmlinuz-4.4.0-87-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.4.0-87-generic /boot/vmlinuz-4.4.0-87-generic
update-initramfs: Generating /boot/initrd.img-4.4.0-87-generic

gzip: stdout: No space left on device
E: mkinitramfs failure cpio 141 gzip 1
update-initramfs: failed for /boot/initrd.img-4.4.0-87-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error processing package linux-image-extra-4.4.0-87-generic (--purge):
 subprocess installed post-removal script returned error exit status 1
Errors were encountered while processing:
 linux-image-extra-4.4.0-87-generic