--mixed

--mixed option is default one so when you do git reset <commit-sha> it is same as you do git reset --mixed <commit-sha>, and what this command does is: it will reset state of your Staging Area to the state of the specified commit, but it will not reset your Working Directory. Let's see this using examples so that you can have a better understanding of --mixed option.

Suppose we add a new file to the Staging Area and we make a new commit.

➜  git-basics-beginners git:(master) ✗
 touch git-mixed-example && git add git-mixed-example && git commit -m "Add git-mixed-example file"
[master 8dca7b2] Add git-mixed-example file
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 git-mixed-example

we can see that we have a new commit:

➜  git-basics-beginners git:(master) ✗ git --no-pager log --oneline
8dca7b2 (HEAD -> master) Add git-mixed-example file
7aa9dca Update index.js file
1a90861 (origin/master) Improve Git Log section

now, let's do git reset to the previous commit the one with 7aa9dca SHA-1 where we were before adding git-mixed-example file.

➜  git-basics-beginners git:(master) git reset --mixed 7aa9dca
➜  git-basics-beginners git:(master) ✗ git status
On branch master
Your branch is ahead of 'origin/master' by 1 commit.
  (use "git push" to publish your local commits)

Untracked files:
  (use "git add <file>..." to include in what will be committed)

  git-mixed-example

nothing added to commit but untracked files present (use "git add" to track)

By running git status we can see that we don't have our new file in the Staging Area and our Working Directory contains git-mixed-example file. And if you do git log you can notice that there is no more 8dca7b2 commit our, HEAD and branch refs are now pointing to 7aa9dca commit, exact same commit on which we were before committing git-mixed-example file.

➜  git-basics-beginners git:(master) ✗ git --no-pager log --oneline
7aa9dca (HEAD -> master) Update index.js file