This lesson's interactive features are locked, please to keep using them

Arguments

BookBot is done! Almost...

You've probably noticed that most CLI tools you use (ls, cd, etc.) are not limited to a single "hardcoded" input. Right now, bookbot can only analyze books/frankenstein.txt. That's not very useful.

Let's update the program so we can pass in any book path instead of using a hardcoded value.

System Arguments

Python's built-in sys module provides access to command-line arguments in the terminal. In particular, sys.argv is a list of strings representing the arguments passed to the script.

The first item in the list is the script name; the rest are the arguments. For example, python3 main.py creates a sys.argv list that looks like this:

print(sys.argv)
# Prints ['main.py']

And python3 main.py books/frankenstein.txt creates a sys.argv list that looks like this:

print(sys.argv)
# Prints ['main.py', 'books/frankenstein.txt']

print(len(sys.argv))
# Prints 2

print(sys.argv[0])
# Prints 'main.py'

print(sys.argv[1])
# Prints 'books/frankenstein.txt'

Assignment

Remove any hardcoded book paths from your code. We'll get the path from the command instead.
At the top of main.py, import the built-in sys module:
```
import sys
```
In your code, check if the sys.argv list has at least two entries. If it doesn't:
- First print a message explaining how to use the program: Usage: python3 main.py <path_to_book>
- Then exit the program with a status code of 1 using sys.exit(1)
Use the second argument in sys.argv as the path to the book file instead of the hardcoded path.
Test your program with python3 main.py books/frankenstein.txt and make sure it works as expected.
Download some more books and test your program with them, adding them to the books directory and passing in their paths as CLI arguments when you run the program. Add at least these two books:
- books/mobydick.txt
- books/prideandprejudice.txt
Use the books that are linked above, or the CLI tests will fail.

You can also run the following commands from the project root to download and create the files:
```
mkdir -p books
curl -L "https://storage.googleapis.com/qvault-webapp-dynamic-assets/course_assets/mobydick.txt" -o books/mobydick.txt
curl -L "https://storage.googleapis.com/qvault-webapp-dynamic-assets/course_assets/prideandprejudice.txt" -o books/prideandprejudice.txt
```

Run and submit the CLI tests from the root of your project.

If the tests pass, it means you've finished building BookBot. Congrats!

I hope you enjoyed this project. It's always good to solidify the things you learn in courses by getting your hands dirty with something practical.