# sudo apt-get autoremove -y
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  linux-headers-3.13.0-101 linux-headers-3.13.0-101-generic
  linux-headers-3.13.0-103 linux-headers-3.13.0-103-generic
  linux-headers-3.13.0-105 linux-headers-3.13.0-105-generic
  linux-image-3.13.0-101-generic linux-image-3.13.0-103-generic
  linux-image-3.13.0-105-generic linux-image-extra-3.13.0-101-generic
  linux-image-extra-3.13.0-103-generic linux-image-extra-3.13.0-105-generic
0 upgraded, 0 newly installed, 12 to remove and 23 not upgraded.
After this operation, 816 MB disk space will be freed.
FATAL -> Failed to fork.