PythonW.exe vs. Python.exe: When to Use Each

Summary of Key Differences:

• python.exe:

  • Console application for CLI scripts
  • Opens a console window
  • Standard streams connected to the console
  • Synchronous execution

• pythonw.exe:

  • GUI application for GUI/no-UI scripts
  • No console window opened
  • Asynchronous execution
  • Standard streams not available

Scenario Analysis:

In your case, you are trying to run a Python script (test.py) that simply prints the letter "a."

• Using pythonw.exe:

  • Since standard streams are not available, print("a") has no effect.
  • The script runs asynchronously, so the command prompt returns immediately.

• Using python.exe:

  • The script opens a new console window and prints "a."
  • Since the script is a console application, the command prompt is blocked until the script terminates, which it does immediately.

Choosing the Correct Executable:

When choosing between python.exe and pythonw.exe, consider the following:

• If you need a console window and access to standard streams, use python.exe.
• If you don't need a console window or standard streams, or if you want to launch GUI applications, use pythonw.exe.

Renaming Python Scripts for Default Execution Association:

You can control the default executable used for Python scripts by changing their file extension:

• *.py files are associated with python.exe
• *.pyw files are associated with pythonw.exe