python3

Start an interactive Python shell

$ python3

$ python3 [script.py]

$ python3 -c "[print('Hello')]"

$ python3 -m [module_name]

$ python3 -m http.server [8000]

$ python3 -m pip install [package]

$ python3 --version

python3 [-BdEhiIOqsSuvVWx?] [-c command] [-m module] [-X option] [script] [args]

python3 is the interpreter for the Python programming language, version 3.x. It executes Python code either interactively or from script files, supporting both procedural and object-oriented programming paradigms.
When invoked without arguments, it starts an interactive REPL (Read-Eval-Print Loop) for experimenting with Python code. With a script file as argument, it executes the script. The -m option allows running installed modules as scripts, enabling functionality like starting HTTP servers, running tests, or managing packages with pip.
Python 3 is the current major version of Python, featuring improved Unicode support, print as a function, integer division changes, and many other enhancements over Python 2 (which reached end-of-life in 2020).

-c command

Execute Python code passed as a string

Run library module as a script

Inspect interactively after running script

Don't write .pyc bytecode files

Optimize generated bytecode

Remove docstrings in addition to -O optimizations

Don't print version and copyright on startup

Don't add user site-packages to sys.path

Don't import the site module

Unbuffered binary stdout and stderr

Verbose mode (trace import statements)

Print Python version and exit

Warning control (error, ignore, always, default, module, once)

Set implementation-specific option

Print help message and exit

Ignore PYTHON* environment variables

On some systems, python may still refer to Python 2; use python3 explicitly to ensure version 3. Virtual environments (venv) are recommended for project isolation. The Global Interpreter Lock (GIL) limits true multi-threaded parallelism. Scripts with Windows line endings may cause issues; use dos2unix if needed.

Python was created by Guido van Rossum and first released in 1991. Python 3.0 was released on December 3, 2008, introducing significant changes that broke backward compatibility with Python 2. The transition period lasted many years, with Python 2.7's end-of-life officially on January 1, 2020. Python has grown to become one of the world's most popular programming languages, widely used in web development, data science, artificial intelligence, scripting, and education.

pip(1), ipython(1), virtualenv(1), perl(1), ruby(1)