What is worth automating

Not every task should be automated. A good candidate has three properties: it is repetitive, it follows clear rules, and doing it by hand is slow or error prone. Renaming 400 photos by date fits all three. Writing a thoughtful reply to a client does not.

A useful way to decide is to estimate how long the task takes each time, how often you do it and how long a script would take to write. If you rename files for ten minutes every week, a script that takes two hours to write pays for itself in about three months, and it never makes a typo.

Typical tasks we will cover

• Sorting downloads into folders by file type
• Renaming files with a consistent date based pattern
• Merging monthly spreadsheets into one summary
• Checking a website or API for new information
• Filling the same web form with data from a spreadsheet
• Emailing a report every Monday morning

The shape of a good script

Every script in this course follows the same structure:

1. Inputs at the top: folder paths, file names and settings in clearly named variables or command line arguments.
2. A dry run mode that prints what would happen without changing anything.
3. The work, split into small functions.
4. Logging that records what was done.
5. Clear errors when something unexpected happens, instead of silently continuing.

This shape makes scripts safe to run and easy to change later. It also means you can hand a script to a colleague without a long explanation.

A word on safety

Scripts are fast, and that includes making mistakes fast. Before running anything that moves or deletes files, test it on a copy of the folder. Always start with the dry run. We will build this habit in the very first project.

In the next lesson we set up a tidy workspace with uv, so every script knows exactly which packages it needs.