After having installed cuda drivers on Ubuntu 16.04, the program told me to make sure to have /usr/local/cuda-8.0 in the PATH variable and /usr/local/cuda-8.0/lib64 in the LD_LIBRARY_PATH variable.

I read, each time the terminal is started it reads the .bashrc file in order to establish its environment variables and environmennt variables should be put into this file. So I checked with

grep PATH .bashrc 


grep LD_LIBRARY_pATH .bashrc 

where in this file the variables are declared to append both paths, but in terror I realized, that there is no such thing as PATH or LD_LIBRARY_PATH inside the .bashrc. And I asked myself: "How are the envirnoment variables declared then?", but no annswer was given. So I went here to ask you Why and How?