i3-wm software package provides improved dynamic tiling window manager, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install i3-wm
i3-wm is installed in your system.
Make ensure the i3-wm package were installed using the commands given below,
$ sudo dpkg-query -l | grep i3-wm *
You will get with i3-wm package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | X Window System software |
| Package | i3-wm |
| Version | 4.7.2-1 |
| Description | improved dynamic tiling window manager |
| Sub Section | x11 |