# pypy > Fast and compliant alternative implementation of the Python language. > More information: . - Start a REPL (interactive shell): `pypy` - Execute script in a given Python file: `pypy {{path/to/file.py}}` - Execute script as part of an interactive shell: `pypy -i {{path/to/file.py}}` - Execute a Python expression: `pypy -c "{{expression}}"` - Run library module as a script (terminates option list): `pypy -m {{module}} {{arguments}}` - Install a package using pip: `pypy -m pip install {{package}}` - Interactively debug a Python script: `pypy -m pdb {{path/to/file.py}}`