remove env setting from code and just add to readme

pynxtools/nexus/README.md

@@ -35,4 +35,13 @@ export 'NEXUS_DEF_PATH'=<folder_path_that_contains_nexus_defs>
 
 Following example dataset can be used to test `read_nexus` module `tests/data/nexus/201805_WSe2_arpes.nxs`.
 This is an angular-resolved photoelectron spectroscopy (ARPES) dataset and it is formatted according to
-the [NXarpes application definition of NeXus](https://manual.nexusformat.org/classes/applications/NXarpes.html#nxarpes).
+the [NXarpes application definition of NeXus](https://manual.nexusformat.org/classes/applications/NXarpes.html#nxarpes).
+
+
+A note to Windows users: if you run `read_nexus` from `git bash`, you need to set the environmental variable
+`MSYS_NO_PATHCONV` to avoid the [path translation in Windows Git MSys](https://stackoverflow.com/questions/7250130/how-to-stop-mingw-and-msys-from-mangling-path-names-given-at-the-command-line#34386471).
+The easiest way is to prefix the `read_nexus` call with `MSYS_NO_PATHCONV=1`:
+
+```
+MSYS_NO_PATHCONV=1 read_nexus -c /NXarpes/ENTRY/INSTRUMENT/analyser
+```

pynxtools/nexus/nexus.py

@@ -776,10 +776,6 @@ def process_nexus_master_file(self, parser):
 )
 def main(nexus_file, documentation, concept):
     """The main function to call when used as a script."""
-    import platform
-
-    if platform.system() == "Windows" and "Git" in os.environ["SHELL"]:
-        os.environ["MSYS_NO_PATHCONV"] = "1"
     logging_format = "%(levelname)s: %(message)s"
     stdout_handler = logging.StreamHandler(sys.stdout)
     stdout_handler.setLevel(logging.DEBUG)