The goal of this talk in to introduce the applications of the command-line to support the mathematician in their work and writing, independently of the field. In the first part, we will discuss what a program is as well as cover the basics of what the command-line is and how it works, its standard tools, and demonstrate its capabilities with various examples. In the second part, we will focus on how to use the command-line in order to organize our workflow, keep a flexible and detailed history of our changes, as well as collaborate with others using the standard version control software Git. We will detail its local usage (commits, branches, merges, hooks, etc) as well as its remote capabilities in conjunction with cloud services like GitHub.