How do i quickly revert back from a commit in git?

giraffelife

I modified my README.md file and added a Sixth line but it'a duplicate and I want to get it back to a previous commit, which I know to be how I want my git repository to be in.

Below shows my Sixth line added.

$ git status
On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   README.md

no changes added to commit (use "git add" and/or "git commit -a")
$ git diff
diff --git a/README.md b/README.md
index 9f28333..10d8f68 100644
--- a/README.md
+++ b/README.md
@@ -7,3 +7,5 @@ Third Line: I got straight to bed
 Fourth Line: and I dream of running the marathon
 
 Fifth Line:  but I don't dress up in a silly costume I'm a serious runner
+
+Sixth Line: Today i woke up and went running

$ cat README.md 
First Line: Today i woke up and went running

Second Line: When I get back from running I'm tired

Third Line: I got straight to bed

Fourth Line: and I dream of running the marathon

Fifth Line:  but I don't dress up in a silly costume I'm a serious runner

Sixth Line: Today i woke up and went running

To get it back to the last required commit, then an easy way is to run a git reset, with options --hard.
```bash
$ git reset --hard
HEAD is now at 091ffd1 My commit of the fifth line again

$ cat README.md 
First Line: Today i woke up and went running

Second Line: When I get back from running I'm tired

Third Line: I got straight to bed

Fourth Line: and I dream of running the marathon

Fifth Line:  but I don't dress up in a silly costume I'm a serious runner