add sudo -H

docs/Readme-Python.txt

@@ -403,6 +403,8 @@ ou
 > sudo pip install <package> 
 ou
 > python3 -m pip install --user <package>  # instead
+ou
+> sudo -H python3 -m pip install <package>
 
 A tester:
 Then I recommend adding the following aliases to your .bashrc:
@@ -486,12 +488,16 @@ Developpement:
 > pip install pynmea2
 > pip install pySerial
 > pip install netCDF4
+> pip install netCDF4 
+> pip install matplotlib
 > pip install seawater
 > pip install numpy
 > pip install PyInstaller
 > pip install PySimpleGUI
 > pip install ConfigParser 
 
+
+
 Pour utiliser QT au lieu de Tk
 > pip install PySimpleGUIQt
 > pip install PySide2
@@ -543,4 +549,4 @@ From https://github.com/jgrelet/oceano2python
 Merge made by the 'recursive' strategy.
  README.md | 2 ++
  1 file changed, 2 insertions(+)
- create mode 100644 README.md
\ No newline at end of file
+ create mode 100644 README.md