How to Make Python Recite a Blessing Before Every Run – A Black‑Magic Trick

As programmers fear bugs, this article shares a quirky Python "black magic" technique that makes the interpreter automatically recite a short blessing before executing any code, aiming to keep the program error‑free.

The method leverages the fact that when you log into a Linux server via SSH, the .bash_profile file is sourced. Python does not have an equivalent by default, so we create a custom environment file.

First, use the site module to locate a suitable user‑site directory and create it with mkdir -p. Inside that directory, add a usercustomize.py file (the core script that prints the blessing). The file’s content is shown below:

After placing this file, any command such as python xxx.py or launching the interactive python shell will first display the blessing text.

For a more controlled approach in the interactive shell, you can create a separate startup script (e.g., startup.py) with the same content and set the environment variable PYTHONSTARTUP to point to it: export PYTHONSTARTUP=/Users/MING/startup.py This ensures the script runs automatically whenever the Python REPL starts. However, this method only affects the interactive shell, not scripts executed directly.

To apply a similar effect when running scripts, a crude workaround is to manually load the startup script before your main code, as illustrated in the following image:

Both techniques are documented in the "Python Black Magic Guide" v2.0 on GitHub, offering a playful way to embed a protective mantra into your Python workflow.