1. save username and password

git config credential.helper store

2. undo the first commit ( assuming there is only one commit in the history)

git update-ref -d HEAD

3. undo the last (n) commits and return the changed files to staging area

git reset --soft HEAD~n

4. print the number of commits on all branches grouped by authors

git shortlog -s -n --all

5. undo a pushed commit in the remote repository, on master branch

git push origin +{commit-id}^:master

6. See all the upstream repository urls

git remote -v

7. change the author date when committing changes

git commit --date "date-format" -m "commit message"

8. Show the list of branches

git show-branch

9. Show the list of tags on the current branch

git tag

10. Show all the configurations for the current repository

git config -l

11. remove a file from the staging area

git reset <file_name>

12. remove all files of a folder from the staging area

git reset <folder_name>/

13. see the changes in the files added to the staging area

git diff --staged

14. change the url of remote repository

git remote set-url <remote_name> <url>

15. ignore changes to already tracked files

git update-index --assume-unchanged <file>

another alternative :

git update-index --skip-worktree <file> 

more information on difference between assume-unchanged and skip-worktree.

16. ignore changes to already tracked files in a folder

git update-index --assume-unchanged <folder_name>/

17. undo tip 15 & 16 : start tracking files again

git update-index --no-assume-unchanged [<file> ...]

18. show list of tags, sorted by date descendingly

git tag --sort=-creatordate

19. delete tag from the local repository

git tag --delete tagname

20. delete tag from the remote repository

git push --delete origin tagname 

21. clone all branches in a remote repository

First, clone the remote repository :

git clone "remote repository url"

Then, see what branches exist in this repository

git branch -a

If you just want to take a quick peek at an upstream branch :

git checkout origin/branch_name

Finally, if you want to continue developing on that branch, you should

git checkout -b branch_name

22. see which commit a tag points to

git rev-parse tagname

23. revert branch history to a specific tag, discarding all changes after the tag

git reset --hard tagname

24. revert branch history to a specific tag, keeping all changes after the tag in the staging area

git reset --soft tagname

25. Show both the AUTHOR_DATE and COMMITTER_DATE of commits

git log --format=fuller

26. The difference between GIT_AUTHOR_DATE and GIT_COMMITTER_DATE :

There are two kinds of timestamp in git: a GIT_AUTHOR_DATE and a GIT_COMMITTER_DATE. Although in most cases they both store the same value, they serve slightly different purposes. As the documentation depicts :

The author is the person who originally wrote the work, whereas the committer is the person who last applied the work.

So if, for instance, you send in a patch to a project, the author date will be when you made the original commit but the committer date will be when the patch was applied. Another common scenario is rebasing: rebasing will alter the commit date, but not the author date.

27. changing the AUTHOR_DATE and COMMITTER_DATE of a commit in git

$ export GIT_AUTHOR_DATE="Wed Feb 16 14:00 2037 +0100"
$ export GIT_COMMITTER_DATE="Wed Feb 16 14:00 2037 +0100"
$ git commit ...

28. filtering history of commits in date ranges using since and until options

git log --since='yesterday'

git log --since="1 week ago" --until="yesterday"

29. showing commit history with summary of changes made in each commit

git whatchanged 

also, the since and until options can be used to filter history

git whatchanged --since='2 weeks ago' --until=`2 days ago`

30. delete local and remote branches

to remove local branch

git branch -D branch_name

to remove a remote branch

git push --delete remote_name branch_name

31. see the changes to a file in a commit

git show commit_hash -- file_name

32. close/archive a branch

First, tag the tip of the branch by archiving it, and then delete the branch.

git tag archive/<branchname> <branchname>
git branch -d <branchname>
git checkout master

The branch is now deleted and can be retrieved later by checking out the tag and recreating it.

git checkout archive/<branchname>
git checkout -b new_branch_name

or alternatively :

git checkout -b new_branch_name archive/<branchname>

33. rename a branch

First rename your local branch. If you are on the branch you want to rename:

git branch -m new-name

If you are on a different branch:

git branch -m old-name new-name

Then, delete the old-name remote branch and push the new-name local branch.

git push origin :old-name new-name

Finally, reset the upstream branch for the new-name local branch. Switch to the branch and then:

git push origin -u new-name

34. revert/undo the last rebase

Rebase leaves the old state as ORIG_HEAD, so we can revert the last rebase by running:

git reset --hard ORIG_HEAD

35. move commits from one branch to another

suppose you have made a single legitimate commit on a wrong branch and now you want to move the changes to the correct one.

First, on the wrong branch, reset the changes you've committed :

git reset --soft HEAD~1

Now the changes are back in the staging area. Stash them :

git stash

Then, checkout into the correct branch

git checkout correct_branch_name

And just pop the stashed files

git stash pop

Now if you do a git status, you'll see the changes are in the staging area of the correct branch and ready to be committed.

36. show all branches(remote and local) that contain a specific tag

git branch -a --contains tag_name

37. update the local list of remote branches

git update remote origin --prune

38. difference between git stash pop and git statsh apply

git stash pop = git stash apply && git stash drop.

git stash pop throws away the (topmost, by default) stash after applying it, whereas git stash apply leaves it in the stash list for possible later reuse (or you can then git stash drop it).

This happens unless there are conflicts after git stash pop, in this case, it will not remove the stash, behaving exactly like git stash apply.

39. show commit history with tags and branch names

git log --decorate

40. checkout a remote branch in a newly-cloned repository

git checkout -b [branch_name] origin/[branch_name]

41. rebasing feature branch with master

Assuming you are on your working branch and you are the only one working on it.

git fetch && git rebase origin/master

42. show history of commits made on branch

To summarize the log output to commits that are made on a specific branch, first checkout the desired branch

git checkout [branch_name]

Then,

git log --graph --decorate --pretty=oneline --abbrev-commit --first-parent

43. remove all staged changes

git checkout -- .

44. remove staged changes of a file

git checkout -- [filename]