Take your Git practice to the next level

echo "dingdingdingbabababaaaaa" >> theFile # (1)
git add theFile
echo "blah" > theFile # (2)
git commit -m "done"

$ git init pouet && cd pouet
$ git commit -m "initial commit" --allow-empty
$ echo abc > .git/refs/heads/paf

$ git init pouet && cd pouet
$ git commit -m "initial commit" --allow-empty
$ echo abc > .git/refs/heads/paf
$ git branch
* master
  paf

git reset HEAD~

git reset --hard HEAD~2

$ git reflog
f7d3b1 HEAD@{0}: commit (amend): Added reset + compulsory lolcat
440a3bf HEAD@{1}: commit (amend): Added reset + details
c830885 HEAD@{2}: commit: Ajout reset
36b4dce HEAD@{3}: commit: Passe sur les ajustements: ff, intro...
5ef0aa8 HEAD@{4}: commit (amend): On sa mis dacor
8e51635 HEAD@{5}: rebase -i (finish): returning to refs/heads/master
8e51635 HEAD@{6}: rebase -i (fixup): On s'a mis dacor
b6d8c99 HEAD@{7}: rebase -i (pick): On s'a mis dacor

git init repo1 && cd repo1 && git commit -m "Initial 1" --allow-empty && cd ..
git init repo2 && cd repo2 && git commit -m "Initial 2" --allow-empty
git remote add other file://$PWD/../repo1
git fetch other
git merge other/master -m "let's merge them"

git log --oneline --graph
*   c2be901 let's merge them
|\
| * 1763514 Initial 1
* 8208b0a Initial 2

Git.cloneRepository()
   .setDirectory("/path/to/git/repository")
   .setURI("git://gitserver/somerepo.git")
   .setBare(false)
   .call();

Git.open("/some/repository")
   .fetch()
   .setRemoveDeletedRefs(true)
   .setTagOpt(TagOpt.FETCH_TAGS)
   .call();