Powerful Git Command

1. return back to the last commit:
    git checkout -f

2. return back to any commit:
    "git hist" to show all the commit
    "git checkout 7-letter code" to change the HEAD
    do not change the branch before create a new branch, if not, the work will be lost.

3. create a new branch and switch over, delete
     "git checkout -b name_new_branch "

4. start up and set up personnel information
    git init
    git config --global user.name "your name"
    git config --global user.email "your_email@whatever.com"

5. restore the modification not yet staging
    git checkout "file"

6. restore the modification staging but not yet committing
    git reset HEAD^

7. squashing commits
    git rebase -i HEAD~num_of_commit_to_squash

8. patch
    make a patch between the current branch and the master: git diff master > file.patch
    after switching to the master, apply the patch: git apply file.patch
    git apply -check for verifying the availability of the patch
9. modify the latest commit
    git commit -amend -m "new commit message"