Updated tutorial:
What is Theos?
Theos is a cross-platform suite of development tools for managing, developing, and deploying iOS software without the use of Xcode.
Theos is primarily used for jailbreak-centric iOS development (such as MobileSubstrate extensions, PreferenceLoader bundles, and applications intended for distribution in Cydia), but can be used for other types of projects as well. This can be helpful for someone wishing to develop an iPhone SDK-based application without using Mac OS X or Xcode to do so, as Theos can be used on Linux and iOS as well. Requirements
Jailbroken iDevice
Cydia
These two repos added to Cydia: nix.howett.net/theos & coolstar.org/publicrepo https://sdks.website/ Video Tutorial
Leave comments and questions below if you get stuck.
Old tutorial: http://iosgods.com/topic/656-tutorialvideo-how-to-set-up-theos-on-your-idevice-ios7ios8/
If you're getting "You did not specify a target , and the "" platform does not define a default target. Stop" error when compiling your project, look at the fix posted here: http://iosgods.com/topic/4370-error-compiling-tweak-you-did-not-specify-a-target-and-the-platform-does-not-define-a-default-target/