Lesson 1 of 2

Scripting Fluency

Writing a one-off migration script under time pressure starts with knowing which language actually fits the job, not defaulting to whichever one you know best.

The four languages

Four languages cover most of the scripting and tooling work a web developer actually does.

Python

The default choice for a quick script, data wrangling, or gluing two APIs together — a huge standard library, minimal ceremony to get started.

JavaScript / Node.js

Runs everywhere a browser does, plus the server via Node — the one language you can't avoid as a web developer regardless of what else you know.

TypeScript

JavaScript plus a type system — catches a whole category of bugs (wrong shape, undefined access) at compile time instead of in production.

Bash

The glue between everything else — chaining commands, automating a repetitive terminal task, or writing the script that runs in CI.

Picking the right tool for a one-off script

A few heuristics cover most decisions.

Reach for Bash when the task is mostly chaining existing CLI tools together. Reach for Python when you need real data structures, explicit error handling, or the script will be read and modified by someone else later. Reach for Node/TypeScript when the script needs to share code or types with an existing JS/TS codebase.

Exercises

Compare the two implementations below, then work through both exercises.

# Bash: quick, one-off, fine for this scope
du -ah . | sort -rh | head -n 5

# Python: same task, but now it's testable, reusable, and handles edge cases
from pathlib import Path

sizes = sorted(
    ((p, p.stat().st_size) for p in Path('.').rglob('*') if p.is_file()),
    key=lambda x: x[1],
    reverse=True,
)
for path, size in sizes[:5]:
    print(f"{size:>12} {path}")

Concept check

Answer in your head first, then click a question to reveal the answer.

Scenario checklist

Work through the sample comparison and check each item off. Progress is saved in your browser.

Identify what the Bash version actually does, line by lineIdentify what the Python version does the same, and what it addsDecide which you would reach for if this needed to run in a CI pipeline dailyDecide which you would reach for if a teammate needed to reuse and modify itDescribe one edge case the Bash version would mishandle that Python handles explicitly

Go deeper

These primers are a starting point. Read the primary sources to build real fluency.

Python Docs: The Python TutorialThe official starting point for reading and writing Python Node.js Docs: Introduction to Node.jsWhat Node actually is, and how it differs from JavaScript in the browser TypeScript Docs: The HandbookThe type system layered on top of JavaScript GNU: Bash Reference ManualThe definitive reference for the shell scripting glue behind CI and automation

Training Notes

What building this project taught me.

This module is the prerequisite, not the flagged gap

Full-Stack Production Bar (the next lesson) was the named gap in the job-hunting scan. This lesson comes first because picking up an unfamiliar language under pressure assumes general scripting fluency already exists.

The comparison below is illustrative, not a recommendation to always prefer one

Neither Bash nor Python is "better" in general — the point of the exercise is recognizing which trade-offs matter for a given script's expected lifespan and audience.