JupyterLab installation with pip3 - jupyter-lab

Question

I installed JupyterLab with
pip3 install jupyterlab --user
Yet, when trying I try to launch it (jupyter lab), I get the following error:
Error executing Jupyter command 'lab': [Errno 2] No such file or directory
The JupyterLab installation guide on github says that: "If installing using pip install --user, you must add the user-level bin directory to your PATH environment variable in order to launch jupyter lab"
But I don't what that means, I greatly appreciate any help. I am using Ubuntu 18.04

Answer 1

As said by the guide itself you need to add the user-level bin directory to your PATH environment variable, in order to do so you need at first spot which is the bin folder where Jupyter lab has been installed, and after that you can add that path with a simple command:
export PATH=$PATH:/path/to/your/jupyterlab/bin/directory
and it's done. You can check if you added it by running this other command:
echo $PATH
And you should see the content of PATH variable.
This method though will just add that variable for the current shell, meaning that when you close the terminal you lose the change in the variable. In order to make it permanent you need to edit another file which is ~/.bashrc.
One thing though, it's really important that you just add this line to the file:
PATH=$PATH:/path/to/your/jupyterlab/bin/directory
without changing all the rest of the file if you don't know what you are doing.
To give you a recap on what to do to make it permanent open a new shell and type:
gedit ~/.bashrc
This will open the file where you need to add the "export PATH...etc" command right at the end of the file in a new line. Then save the changes and reboot, from now on you should be able to open Jupyter lab directly from a shell with the command:
Jupyter lab