how to launch recent Jupyter QtConsole on Windows without a console window

Question

This older question appears to be out of date.

It used to be (based on reading git repos and the qtconsole issue tracker ) you could launch the Jupyter QtConsole without a console window running the background with:

pythonw -m jupyter qtconsole

However, in recent versions of Jupyter, this still launches the background console window.

I am wondering if anyone knows how to launch the QtConsole without the annoying console window. I know you can do this from the Anaconda Navigator program, but I don't want to launch one program so that I can then launch another program. I would prefer to have a simple batch script or even a python script so that I can launch with a Start Menu shortcut

Running the module directly also does not work:

pythonw -c "from qtconsole.qtconsoleapp import main; main()"

This still launches a new console window as in the picture, so I don't really know if this is possible in some straightforward way, or if the Anaconda Navigator is doing some black magic to make this happen

Answer 1

There are two problems here:

• %CONDA_PREFIX%\\Scripts\\jupyter-qtconsole.exe marked as console executable ( Subsystem field in PE optional header )
• the -m ipykernel_launcher <etc> subprocess started with python.exe even if the launcher was started with pythonw .
  • This one I was able to track to %CONDA_PREFIX%\\share\\jupyter\\kernels\\python3\\kernel.json . It uses a full path to the executable thus doesn't trigger the logic in jupyter_client\\manager.py that replaces certain patterns with sys.executable .

Both of these are specific to Anaconda and do not happen with the stock Python. As such, file a bug against https://github.com/conda-forge/qtconsole-feedstock to get this fixed.

These are the workarounds:

• For the first bug, run pythonw <Scripts_dir>\\jupyter-qtconsole-script.py which is the script that the .exe wraps.
  (This is Anaconda-specific. Regular Python uses a different wrapping mechanism. Anaconda must be patching setuptools or something.)
• For the second one, replace the full path in the aforementioned kernel.json with " python ". This change will be overwritten when you update the ipykernel package that this file belongs to (this can be checked by searching for it in %CONDA_PREFIX%\\pkgs ).

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The OP reports that this solution may break other Anaconda packages . I believe those that break make assumptions about the availability of standard streams. Though it too counts as a bug in my book, it must be coming from the fact that Anaconda packages aren't tested with this setup.

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To create a shortcut/batch file to run the above command in Anaconda Prompt environment, see eg How to make batch files run in anaconda prompt .