python -c and scripts

Learn to run scripts from the command line.

What is a script file?

You can save Python code to a file and run it from the terminal. This file is called a script and has the .py extension.

For example you write print("Hello") into hello.py and run it with python3 hello.py.

Unlike the REPL, a script file runs all the code from top to bottom. The REPL runs line by line. For large programs you use a script file.

Sometimes you want to run a short piece of code without saving it to a file. For this you use the python3 -c flag:

python3 -c 'print("Hello")'

-c is short for 'command'. It runs the code inside the quotes and exits. It is very handy for a quick calculation or check.

Unlike a script file this is not permanent; the code is not saved.

Complete the script below so that it prints Script ran to the screen with print. Add an explanatory comment at the top.

Show example solution

# This script prints a message to the screen
print("Script ran")

Write the script extension

# file name: hello____
print("Hello")

Show answer

# file name: hello.py
print("Hello")