Install Komodo Edit in Ubuntu from PPA:
Komodo Edit gets a PPA on launchpad.net. So far, it provides the latest packages for Ubuntu 12.10 Quantal and 12.04 Precise. To install it, hit Ctrl+Alt+T, copy and paste following commands into terminal and run one by one.
Add the ppa to repository:
sudo add-apt-repository ppa:mystic-mirage/komodo-edit
sudo apt-get update
Install Komodo Edit from the repository:
sudo apt-get install komodo-edit
Once installed, you can open Komodo Edit from the Unity Dash Home. Or in file Properties window Open With tab, choose Komodo Edit and set as default.