Run Your First Python Command-Line App

Open a terminal:

• Windows: PowerShell or Command Prompt
• macOS: Terminal
• Linux: Terminal

Run:

python --version

python --version

You should see something like Python 3.12.2.

If that command fails, try:

python3 --version

python3 --version

On Windows, you can also try:

py --version

py --version

Remember which command worked—you’ll use it again.

If none works, install Python 3 from python.org/downloads, reopen the terminal, and repeat the check.

In the terminal, run these commands one at a time:

mkdir python-hello
cd python-hello

mkdir python-hello
cd python-hello

Check your location:

• Windows: dir
• macOS/Linux: pwd

The folder name or path should include python-hello.

Open a plain-text or code editor and create a file named exactly:

hello.py

hello.py

Save it inside the python-hello folder. Make sure it is not named hello.py.txt.

Using that pattern, type two statements in hello.py:

1. The first must print exactly Hello, world!
2. The second must print a sentence personalized with your name or an interest, such as introducing your name

Keep quotation marks around each line of text. Save the file.

Return to the terminal. Use the Python command that worked earlier:

python hello.py

python hello.py

Or:

python3 hello.py

python3 hello.py

Or on Windows:

py hello.py

py hello.py

Your terminal should show two lines in this shape:

Hello, world!
[your personalized sentence]

Hello, world!
[your personalized sentence]

Check the first line carefully: it needs the capital H, comma, space, and exclamation mark.

• “No such file” or “can’t open file”: confirm the terminal is inside python-hello, then list its files with dir or ls.

• SyntaxError: check that both strings have matching quotation marks and both calls have closing parentheses.

• Only one line appears: confirm the file contains two separate print() calls, then save and run it again.