How to Verify Which Python Binary Your Code Actually Runs

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Developers often assume commands like 'python' or 'pip' point to the correct interpreter, but this can silently cause errors in scripts and CI pipelines. On many systems, 'python' is either missing or aliased differently from 'python3', making explicit checks essential. Virtual environments add another layer of confusion, as a new shell session may not activate the venv even if the directory exists. Similarly, 'pip' and 'python3 -m pip' can belong to different interpreters, leading to packages being installed in the wrong environment. A short shell audit script using commands like 'command -v', 'sys.executable', and exit code checks can quickly confirm which binaries are actually in use.

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