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+---
+title: "Getting the .ipynb Notebook File Location From a Running Jupyter Lab Notebook"
+date: 2025-06-29T23:42:00+01:00
+summary: >
+    If you need to get the path of the ipynb file in a running #Jupyter notebook, this one-liner will do the trick. It
+    seems chatgpt is confused, and a bunch of other approaches on the web look fragile and/or unnecessarily complex to
+    me.
+---
+
+If you need to get the path of the ipynb file in a running #Jupyter notebook, this one-liner will do the trick. It seems
+chatgpt is confused, and a bunch of other approaches on the web look fragile and/or unnecessarily complex to me.
+
+.. code:: python
+
+    import sys
+    Path(json.loads(Path(sys.argv[-1]).read_bytes())['jupyter_session'])
+
+The way this works is that for each notebook, jupyter starts a python "kernel" process that actually runs the notebook's
+code. That kernel gets a json file with info on the notebook's location on the disk passed through its command line.
+Since we're running code in that exact python process, we can just grab that json file from sys.argv, and read it
+ourselves.