Sage 8.1: jupyter does not start on MacOS Sierra

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I have just installed Sage 8.1 on MacOS Sierra. After I launch the application, I am told Jupyter did not start and I get offered to open the log. Doing so, here is what I get there

/Applications/SageMath-8.1.app/Contents/Resources/sage/src/bin/sage-env: line 322: [: /Applications/SageMath-8.1: binary operator expected Traceback (most recent call last): File "/Applications/SageMath-8.1.app/Contents/Resources/sage/src/bin/sage-notebook", line 13, in <module> from sage.env import SAGE_ROOT ImportError: No module named sage.env