installation.md

@@ -100,7 +100,7 @@ sudo apt install git python3 python3-venv build-essential python3-dev cmake
 The following packages aren't necessary, but if installed the system packages will be used instead of copies installed later by pip.
 
 ```
-sudo apt-get install -y build-essential python3-numpy python3-matplotlib python3-mako python3-mock python3-scipy python3-pil python3-cartopy python3-pil python3-netcdf4 python3-h5py libgeos-dev python3-pyqt5
+sudo apt install build-essential python3-numpy python3-matplotlib python3-mako python3-mock python3-scipy python3-pil python3-cartopy python3-pil python3-netcdf4 python3-h5py libgeos-dev python3-pyqt5
 ```
 
 If you want to force a local install, perhaps for testing, omit `--system-site-packages`. Run these as your normal user: