$ dpkg -l | awk '$2 ~ /linux-image/ {print$2}' | xargs sudo apt-get -y purge
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  wireless-regdb nvidia-settings-319 crda
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  linux-image-3.2.0-72-generic* linux-image-3.2.0-74-generic* linux-image-3.2.0-75-generic*
  linux-image-3.2.0-76-generic* linux-image-3.2.0-77-generic* linux-image-3.2.0-86-generic*
  linux-image-3.2.0-87-generic*
0 upgraded, 0 newly installed, 7 to remove and 0 not upgraded.
After this operation, 0 B of additional disk space will be used.
(Reading database ... 432916 files and directories currently installed.)
Removing linux-image-3.2.0-72-generic ...
Purging configuration files for linux-image-3.2.0-72-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-72-generic /boot/vmlinuz-3.2.0-72-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-72-generic /boot/vmlinuz-3.2.0-72-generic
Removing linux-image-3.2.0-74-generic ...
Purging configuration files for linux-image-3.2.0-74-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-74-generic /boot/vmlinuz-3.2.0-74-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-74-generic /boot/vmlinuz-3.2.0-74-generic
Removing linux-image-3.2.0-75-generic ...
Purging configuration files for linux-image-3.2.0-75-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-75-generic /boot/vmlinuz-3.2.0-75-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-75-generic /boot/vmlinuz-3.2.0-75-generic
Removing linux-image-3.2.0-76-generic ...
Purging configuration files for linux-image-3.2.0-76-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-76-generic /boot/vmlinuz-3.2.0-76-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-76-generic /boot/vmlinuz-3.2.0-76-generic
Removing linux-image-3.2.0-77-generic ...
Purging configuration files for linux-image-3.2.0-77-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-77-generic /boot/vmlinuz-3.2.0-77-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-77-generic /boot/vmlinuz-3.2.0-77-generic
Removing linux-image-3.2.0-86-generic ...
Purging configuration files for linux-image-3.2.0-86-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-86-generic /boot/vmlinuz-3.2.0-86-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-86-generic /boot/vmlinuz-3.2.0-86-generic
Removing linux-image-3.2.0-87-generic ...
Purging configuration files for linux-image-3.2.0-87-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-87-generic /boot/vmlinuz-3.2.0-87-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-87-generic /boot/vmlinuz-3.2.0-87-generic