add 4 tips

README.md

@@ -274,3 +274,44 @@ And finally, let's cherry-pick the commit for bug #14:
 ```
 (14)$ git cherry-pick 5ea5173
 ```
+## I want to discard local commits so my branch is the same as one on the server
+
+Confirm that you haven't pushed your changes to the server.
+
+`git status` should show how many commits you are ahead of origin:
+
+```
+$ git status
+# On branch bug123
+# Your branch is ahead of 'origin/bug123' by 2 commits.
+#   (use "git push" to publish your local commits)
+#
+```
+
+```
+# one commit
+git reset --hard HEAD^
+# two commits
+git reset --hard HEAD^^
+# four commits
+git reset --hard HEAD~4
+```
+
+## I want to discard my local, uncommitted changes
+
+```
+git reset --hard
+# or
+git checkout -f
+```
+
+## I want to add changes in one file to two different commits
+
+`git add` will add the entire file to a commit. `git add -p` will allow to interactively select which changes you want to add.
+
+## I want to remove a file from git but keep the file
+
+```
+git rm --cached log.txt
+```
+