python: pyenv command without home

linux/workstation/python.markdown

@@ -54,8 +54,8 @@ This creates a custom configuration `~/.local/share/jupyter/kernels/opt-software
 
 ### Use pyenv to install custom Python versions
 
-If you want to install your own Python versions, watch out to either not source our environment, or to redirect the pyenv installation to a location, where you have write access (either the local scratch or your home folder).
+If you want to install your own Python versions, watch out to either not source our environment, or to redirect the pyenv installation to a location, where you have write access (either the local scratch or some project folder on your group share).
 
 ```
-PYENV_ROOT=$HOME pyenv install <version>
+PYENV_ROOT=/path/to/project pyenv install <version>
 ```