$ sudo apt-get install linux-headers-generic
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  linux-headers-3.13.0-46 linux-headers-3.13.0-46-generic
The following packages will be REMOVED:
  linux-image-extra-3.13.0-44-generic
The following NEW packages will be installed:
  linux-headers-3.13.0-46 linux-headers-3.13.0-46-generic
The following packages will be upgraded:
  linux-headers-generic
1 upgraded, 2 newly installed, 1 to remove and 52 not upgraded.
8 not fully installed or removed.
Need to get 9.605 kB of archives.
After this operation, 75,2 MB disk space will be freed.
Do you want to continue? [Y/n] 
Get:1 http://br.archive.ubuntu.com/ubuntu/ trusty-updates/main linux-headers-3.13.0-46 all 3.13.0-46.75 [8.888 kB]
Get:2 http://br.archive.ubuntu.com/ubuntu/ trusty-updates/main linux-headers-3.13.0-46-generic amd64 3.13.0-46.75 [714 kB]
Get:3 http://br.archive.ubuntu.com/ubuntu/ trusty-updates/main linux-headers-generic amd64 3.13.0.46.53 [2.852 B]
Fetched 9.605 kB in 22s (424 kB/s)                                             
(Reading database ... 700059 files and directories currently installed.)
Removing linux-image-extra-3.13.0-44-generic (3.13.0-44.73) ...
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 3.13.0-44-generic /boot/vmlinuz-3.13.0-44-generic
run-parts: executing /etc/kernel/postinst.d/dkms 3.13.0-44-generic /boot/vmlinuz-3.13.0-44-generic
Error! Your kernel headers for kernel 3.13.0-44-generic cannot be found.
Please install the linux-headers-3.13.0-44-generic package,
or use the --kernelsourcedir option to tell DKMS where it's located
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.13.0-44-generic /boot/vmlinuz-3.13.0-44-generic
update-initramfs: Generating /boot/initrd.img-3.13.0-44-generic
cp: cannot stat ‘/sbin/rmmod’: No such file or directory
E: /usr/share/initramfs-tools/hooks/kmod failed with return 1.
update-initramfs: failed for /boot/initrd.img-3.13.0-44-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error processing package linux-image-extra-3.13.0-44-generic (--remove):
 subprocess installed post-removal script returned error exit status 1
E: Sub-process /usr/bin/dpkg returned an error code (1)