How can I change them by directly editing the file ? echo $PATH returns this : /usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
Global path settings: /etc/environment
User specific settings: ~/.bashrc
The paths are normally updated by the system when you install packages or change configurations e.g. proxy settings. Anyway, you can also change the paths or other environment variables editing the above files directly.