I am learning git, and I am a beginner. I have just finished CodeCademy's Git course (

CodePudding user response：

The backup file is created by the editor, not git. It is just another file. In your figure, you created an empty repository and there are three files in the working directory (a.txt, b.txt, README.txt). You edited a.txt with gedit, and now there are 4 files (a.txt, a.txt~, b.txt, README.txt). You added a.txt and committed it to the repository. The status now says that there are three other files that it doesn't know about, because they haven't been added to the repository.