Linux Kernel Upgrade / Downgrade in Ubuntu

Sometimes you may want to change the kernel running.

Get list of installed kernel in the system:

dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'

linux-headers-3.5.0-17
linux-headers-3.5.0-17-generic
linux-headers-3.5.0-27
linux-headers-3.5.0-27-generic
linux-headers-3.5.0-28
linux-headers-3.5.0-28-generic
linux-headers-3.5.0-39
linux-headers-3.5.0-39-generic
linux-image-3.5.0-17-generic
linux-image-3.5.0-27-generic
linux-image-3.5.0-28-generic
linux-image-3.5.0-39-generic
linux-image-extra-3.5.0-17-generic
linux-image-extra-3.5.0-27-generic
linux-image-extra-3.5.0-28-generic
linux-image-extra-3.5.0-39-generic

Install version of headers and kernel image
apt-cache search linux-image
Eg. just install the 3.5.0-39 version of kernel
sudo apt-get install linux-image-3.5.0-39-generic

Install 3.5.0-32 version of kernel
sudo apt-get install linux-image-extra-3.5.0-32-generic linux-image-3.5.0-32-generic linux-headers-3.5.0-32-generic linux-headers-3.5.0-34

Update grub to default into the version you just installed.

gksudo gedit /etc/default/grub

Reboot

References
http://askubuntu.com/questions/233380/how-do-i-downgrade-kernel-on-12-10

Helpful Ubuntu and Linux Admin Utilities

SSH with no password

https://help.ubuntu.com/community/SSH/OpenSSH/Keys

Simple Steps

1. On Client (Mac or Linux): create keys

mkdir ~/.ssh
chmod 700 ~/.ssh
ssh-keygen -t rsa

2. Copy only Public Key to the Server or remote host

ssh-copy-id <username>@<host>

If ssh-copy-id not found then do this on the server

cp authorized_keys authorized_keys_Backup
cat id_rsa.pub >> authorized_keys

Software

sudo apt-get install openssh-server

sudo apt-get install openssh-client

Copy files from one machine or folder to another

https://help.ubuntu.com/community/rsync

sudo rsync -azvv /home/path/folder1/ /home/path/folder2

Software

sudo apt-get install rsync