Changing Computer Name in Elementary OS 0.2 (Luna)

It's a simple two-line command to execute:

$sudo gedit /etc/hostname

and replace the old name with the new name. It has to be done here also:

$sudo gedit /etc/hosts

Restart the computer and check the terminal. The changes will be reflected.

Install Numix Theme/Icons on Elementary OS 0.2 (Luna)

$ sudo apt-add-repository ppa:numix/ppa
$ sudo apt-get update
$ sudo apt-get install numix-gtk-theme numix-icon-theme-circle

Install Elementary-Tweaks on Elementary OS 0.2 (Luna)

Elementary Tweaks is an application to configure your eOS desktop. Here's how to install it:

$ sudo apt-add-repository ppa:versable/elementary-update
$ sudo apt-get update
$ sudo apt-get install elementary-tweaks

Now click on System Settings, and you'll see this new icon:

For a try, I've moved my icons 'plank' right:

Install Pacifica theme on Elementary OS 0.2 (Luna)

$ sudo apt-add-repository ppa:elementary-br/projects
$ sudo apt-get update
$ sudo apt-get install pacifica-icon-theme

Now set the theme using the gsettings configuration tool:

$ gsettings set org.gnome.desktop.interface icon-theme "Pacifica"

If you've already installed Elementary Tweaks, the command above is not required. You can just select the Icon Theme and set it.