Learn the Command Line - Online Course
Git - the simple guide - no deep shit - Reference Guide
Learn SQL at Codecademy - Online Course
Try SQL at CodeSchool - Online Course
Data Analyst or Data Scientist track at DataCamp
Overall good grasp of Pandas (Data Structures), Numpy (Scientific and N-dimensional arrays) and Matplot (Data Visualization)
Hadoop: The Definitive Guide (From $24 or included in O'Reilly Safari Books Online Subscription $49/month) - Book
Learning Spark: Lightning-Fast Big Data Analysis (From $19 or included in O'Reilly Safari Books Online Subscription $49/month) - Book