There’s a pattern in shell scripts that makes code harder to read than it needs to be. It looks like this:

if [[ -f "$config_file" ]]; then
  if [[ -r "$config_file" ]]; then
    source "$config_file"
    if [[ -n "$DATABASE_URL" ]]; then
      connect_to_database
      if [[ $? -eq 0 ]]; then
        run_migrations
        # ... and so on
      else
        echo "Connection failed" >&2
        exit 1
      fi
    else
      echo "DATABASE_URL not set" >&2
      exit 1
    fi
  else
    echo "Config not readable" >&2
    exit 1
  fi
else
  echo "Config not found" >&2
  exit 1
fi

You’ve seen this. You’ve probably written this. I haven’t. Sorry, not sorry.

— “Elmo’s got the moves” playing in my head since I typed this article’s title —

I wrote a book on Bash scripting that I’m about to publish. It teaches you how to write Bash, and more importantly, how to write it right.

But cool kids don’t write code anymore, do they?

Maybe the time will never come again when we’ll need to read and understand code ourselves—AI agents will have us covered. Maybe it’s fine. Maybe you don’t need to know the basics.

Testing as a topic is a minefield already when it comes to full-fledged programming languages, let’s not even talk about it for shell scripting.

Or shall we?

You see, whether you write software to test other software, or you just fire up a script from the command line and keep running it over and over again until you nail it, that’s still testing, right?

Have you ever been woken up at night because a script failed six months after you wrote it? Or one year later? Or five years later? — For the love of my life, that thing was supposed to be temporary! There’s nothing more permanent than a temporary solution, they say.

You’ve written Bash scripts before. Maybe you’ve automated a deployment, wrangled some log files, or stitched together a few commands to save time. But as your scripts grow, something changes. What started as a clean 20-line helper becomes a 200-line sprawl. Functions call functions that modify global variables. You copy-paste code between scripts because extracting shared logic feels harder than it should be. The script works, but it’s fragile, and you’re the only person who can maintain it.