We will discuss best practices for python programs that are used from the CLI by system administrators and devops. By looking at the expectations of system administration (service, logging, monitoring), we will see how we can implement it in Python.

Best practices for CLI: - Input (standard input, argument parsing) - Output (standard output, logs) Introduction to linux system administration needs: - Running application as a service - Monitoring

Python is a popular replacement to bash scripts on linux servers. In system administration, it is used both for applications that provide services, and for scripted tools. The context of this talk will be the following environment: - Linux distribution with bash or equivalent - Python 2.7 or 3.x - A modern init system (systemd or equivalent functionalities) In this talk, we will see how sysadmins and devops interact with programs using CLI (Command Line Interface), and how to design a CLI-friendly program. We will see two types of programs and their way of interactions: application running on the background, and tools doing a one-time action. For tools, we will look at argument parsing and the standard input for the user input, as well as the standard output and the log management. For python application running in the background, we will look at how we can package an application as a service, and how it can be controlled from the service manager. We will also look at what output that kind of program can provide (status, logs).