Powerful Text Editor for Markdown and reStructuredText - ReText

Markdown is a text-to-HTML conversion tool for web writers. Markdown allows you to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML).

Thus, “Markdown” is two things:
 * A plain text formatting syntax
 * A software tool, written in Perl, that converts the plain text formatting to HTML.

reStructuredText is an easy-to-read, what-you-see-is-what-you-get plain text markup syntax and parser system. It is useful for in-line program documentation (such as Python docstrings), for quickly creating simple web pages, and for standalone documents. reStructuredText is designed for extensibility for specific application domains. The reStructuredText parser is a component of Docutils.
The primary goal of reStructuredText is to define and implement a markup syntax for use in Python docstrings and other documentation domains, that is readable and simple, yet powerful enough for non-trivial use. The intended purpose of the markup is the conversion of reStructuredText documents into useful structured data formats.

ReText is a simple but powerful text editor for Markdown and reStructuredText.
It is written in Python using Qt libraries, able to run on any platforms.

ReText Features:
 * Full Markdown and reST support
 * Markdown extensions support
 * Tabs and live preview
 * Files auto-save option
 * HTML, PDF, ODT export; Export Extensions
 * Web Pages generator
 * Google Docs uploads
 * CSS styles support
 * HTML syntax highlighting
 * Tags and symbols boxes for quick insert

ReText Installation:
ReText package is available in the default available repository under Ubuntu, you can search "ReText" and install it using Software Center or can install it using command:

sudo apt-get install retext

After successful installation, you can open the font ReText from Unity 'Dash'

Using ReText:
After you open ReText, the main editing area will be shown. You can now type the text in your favorite markup language. You can switch between Markdown and ReStructuredText using "Edit → Default editing mode" menu (if both modules are installed).

For preview, click "Preview" button or press Ctrl+E. To enable two-panel mode, activate "Live Preview" from "Edit" menu or press Ctrl+Shift+E.

To set a font, use "Edit → Change default font" option.

Files are opened and saved just like in all other text editors. To export a file to a different format, use "File → Export" menu.