Atom is text editor from Github its currently in beta . you can build atom for ubuntu by just following steps . Please Note that its only support 64bit ARCH if you are running 32 System then it might not gonna work for you .

Atom is a hackable text editor for the 21st century, built on atom-shell, and based on everything we love about our favorite editors. We designed it to be deeply customizable, but still approachable using the default configuration.

System Requirements

• OS with 64-bit architecture
• node.js v0.10.x
• npm v1.4.x
• libgnome-keyring-dev

lets install some prerequisites

sudo apt-get install python-software-properties
sudo add-apt-repository ppa:chris-lea/node.js  
sudo apt-get update  
sudo apt-get install nodejs curl git-core 
sudo apt-get install libgnome-keyring-dev
npm config set python /usr/bin/python2 -g

okay , how to build

git clone https://github.com/atom/atom
  cd atom
  script/build # Creates application at /tmp/atom-build/Atom
  sudo script/grunt install # Installs command to /usr/local/bin/atom
  script/grunt mkdeb # Generates a .deb package at /tmp/atom-build

or there is PPA from webupd8 team

sudo add-apt-repository ppa:webupd8team/atom
sudo apt-get update
sudo apt-get install atom

you can install using one of above methods .
Github Repository : https://github.com/atom/atom

Update {.text-warning}

Now download deb package from official website

Download