[github] Usages

working with different files

• "Remove a file from a Git repository without deleting it from the local filesystem" https://stackoverflow.com/questions/1143796/remove-a-file-from-a-git-repository-without-deleting-it-from-the-local-filesyste

working with branches

*check the current branch

```git branch``` will show all the branches of the current repo;
the starred one is the branch you are on

• pull from another branch

  git pull is the shorthand for git pull <remote> <branch>, default git pull origin master

  use git remote -v for the remotes;

  use git remote add <remote name> <url> for setting new remote address

• merge another branch

• creating new branches

working with commits

• check commits

git log # check previous commit

• revert the previous commit

git revert <unwanted previous commit hash>

• check some history version of the code

git checkout <test commit hash> # checkout (not "pull" !) a history version of the code