Reload or refresh a current file reading
If you are configuring your emacs via editing .emacs file, it should use this feature to refresh a reading file without closing and reopening it. This means that we want to keep Emacs running and to reload the files opening. Currently, I have found two ways:
The 1st way: C-x C-v Return/Enter
The 2nd way: M-x revert-buffer
 Set the underscore (“_”) is as a part of word
You recognize the underscore not to be a part of words in Emacs. By double-clicking on the words containing underscores, you never choose whole word because the underscore is not considered as a part of word. That also shows at moving the cursor word by word. More especially, Emacs gives a incorrect result in counting the number of words in a selected region. For instance, Emacs will give 4 in the text “Agv Tgdh_p ATP”.
We change Emacs by adding the line: (modify-syntax-entry ?_ “w”) into .emacs configuration file.