Invent With Python - Learn to program Python for free
GNU sed - sed (stream editor) is a Unix utility that parses text and implements a programming language which...
Mode Python Notebooks - Exploratory analysis you can share
Perl - Highly capable, feature-rich programming language with over 26 years of development
Learn Python The Hard Way - One of the best guides to learn Python & coding in general
TXR - Pragmatic, convenient data munging language.