shammimore/git_intro

Tiny repository to showcase a few git principles

git_intro

Tiny repository to showcase a few git principles

Challenges:

A) THE BASICS

1. create an empty directory on your computer and initialize a git repository: git init
2. Navigate into the directory. Create a random textfile (myfile.txt) with some random content.
3. Find out what has changed by running git status

On branch master

No commits yet

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

	myfile.txt

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

4. Tell git to track this file: git add myfile.txt
5. Find out what has changed by running git status: Your file is now in the staging area

On branch master

No commits yet

Changes to be committed:
  (use "git rm --cached <file>..." to unstage)

	new file:   myfile.txt

6. commit the file. Specify a helpful commit message for future reference with -m : git commit -m "add random input to first file"

[master (root-commit) 2f13b9e] add random input to first file
 1 file changed, 1 insertion(+)
 create mode 100644 myfile.txt

7. add more random content to your file. Run git status and see what happens.

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:   myfile.txt

no changes added to commit (use "git add" and/or "git commit -a")

8. Find out what the difference between your commited version of myfile.txt and the current version in your working directory is by running git diff myfile.txt

diff --git a/myfile.txt b/myfile.txt
index d83ec6b..8eb01e5 100644
--- a/myfile.txt
+++ b/myfile.txt
@@ -1 +1,2 @@
 1223457
+12345678

9. Add the changes to the staging area: git add myfile.txt
10. Try running git diff myfile.txt again. It won't show anything, even though your changes are only staged, not committed. To see the difference to your commited version of myfile.txt and the currently staged version, run git diff --staged. (This can be useful if you want to make extra sure you know what you are committing)

diff --git a/myfile.txt b/myfile.txt
index d83ec6b..8eb01e5 100644
--- a/myfile.txt
+++ b/myfile.txt
@@ -1 +1,2 @@
 1223457
+12345678

[If you would want to unstage changes, run git reset HEAD myfile.txt]

11. commit the changes. Don't forget the commit message! git commit -m "even more randomness to this file!"
12. Check the history of your repository: git log (if you have it installed, use tig - its much prettier)

commit 33516ffbc3cbc973958fe5fda665406923390784 (HEAD -> master)
Author: Adina Wagner <adina.wagner@t-online.de>
Date:   Thu Jun 20 15:18:38 2019 +0200

    even more randomness to this file

commit 2f13b9ee08fb4aaa625802a70b8d5694d26b91ee
Author: Adina Wagner <adina.wagner@t-online.de>
Date:   Thu Jun 20 15:03:21 2019 +0200

    add random input to first file

13. put more files into your repository: Call the first file nena.txt and add the lyrics to "99 Luftballons". Add the first 300 digits of pi to pi.txt

14. add and commit these files subsequently, e.g. by adding + committing and specifiying the file name explicitly (git add nena.txt, git commit nena.txt)

15. Delete the last verse from 99 Luftballons. Show the difference with git diff, then add and commit your changes.

diff --git a/nena.txt b/nena.txt
index 77edda7..6256cbb 100644
--- a/nena.txt
+++ b/nena.txt
@@ -34,11 +34,3 @@ Mann, wer hätte das gedacht
 Dass es einmal soweit kommt
 Wegen 99 Luftballons
 
-99 Jahre Krieg
-Ließen keinen Platz für Sieger
-Kriegsminister gibt’s nicht mehr
-Und auch keine Düsenflieger
-Heute zieh ich meine Runden
-Seh’ die Welt in Trümmern liegen
-Hab’ ‘nen Luftballon gefunden
-Denk’ an dich und lass’ ihn fliegen

16. you realize your second commit ("even more randomness to this file!") did not make sense. Find this commit in the git log and copy the first 6-10 characters from the 40 character long hash git identifies the file in that version with. (here it is 33516ffbc3c)

git log

commit fcc49d7dafedec835bcd1019c59b5cec4fcdd3e0 (HEAD -> master)
Author: Adina Wagner <adina.wagner@t-online.de>
Date:   Thu Jun 20 15:42:39 2019 +0200

    delete last verse from 99 Luftballons

commit 900dd3a52a6c6d2b09e93b2afbec1e44985d54d4
Author: Adina Wagner <adina.wagner@t-online.de>
Date:   Thu Jun 20 15:33:30 2019 +0200

    add 300 digits of pi

commit 17504ee02ff232886c6ceaef1aaf36b1e5dc3bde
Author: Adina Wagner <adina.wagner@t-online.de>
Date:   Thu Jun 20 15:33:14 2019 +0200

    add 99 Luftballons songtext

commit 33516ffbc3cbc973958fe5fda665406923390784
Author: Adina Wagner <adina.wagner@t-online.de>
Date:   Thu Jun 20 15:18:38 2019 +0200

    even more randomness to this file

commit 2f13b9ee08fb4aaa625802a70b8d5694d26b91ee
Author: Adina Wagner <adina.wagner@t-online.de>
Date:   Thu Jun 20 15:03:21 2019 +0200

    add random input to first file

17. Revert this commit: git revert <hash>

18. you are looking for the number 99 in this repository. Instead of opening all files and looking through them, you can run git grep 99 (The output would highlight 99s in your terminal):

nena.txt:Von 99 Luftballons
nena.txt:Von 99 Luftballons
nena.txt:99 Luftballons
nena.txt:Nur 99 Luftballons
nena.txt:99 Düsenflieger
nena.txt:Auf 99 Luftballons
nena.txt:99 Kriegsminister
nena.txt:Wegen 99 Luftballons
pi.txt:141592653589793238462643383279502884197169399375105
pi.txt:82097494459230781640628620899862803482534211706798

B) FORKING, CLONING, REMOTES AND PULL REQUESTS

1. Fork this repository to your own account (click the fork button in the top right corner)

2. Clone your fork of this repository (if you have an SSH key, clone via SSH) git clone https://github.com/<USERNAME>/git_intro.git

3. This clone currently has one remote: Your fork on your Github user account. You can see this by listing the remotes: git remote -v

origin	git@github.com:<USERNAME>/git_intro.git (fetch)
origin	git@github.com:<USERNAME>/git_intro.git (push)

4. Lets make your clone aware of the original Github repository by adding it as a remote: with SSH: git remote add gh-adswa git@github.com:adswa/git_intro.git with HTTP: git remote add gh-adswa https://github.com/adswa/git_intro.git

5. In the directory files/, create a textfile. The name of your textfile should be your first name. The content of the file should be a link to your favourite webcomic. Add and commit this file to the repo.

6. Open the json file zenodo.json in an editor of your choice. Add a (random) affiliation, (random) name, and (random) orcid to your assigned spot, and then add and commit the change.

7. push the new file and the change to zenodo.json to your fork: git push

8. go to your Github account and your fork of this repository. Submit a pull request.

9. on your computer, integrate the changes we collaboratively made to this repository with git pull gh-adswa

BRANCHING & MERGING

1. Within the cloned repository (on your local machine), you want to create a new branch. List all existing branches with git branch -a

* master
  remotes/upstream/master

2. Create a new branch that you name like your last name, and move (checkout) this branch:

git branch Wagner 
git checkout Wagner
  Switched to branch 'Wagner'

[There is a shortcut for the above: git checkout -b Wagner]

3. on this branch, create a new file, add it to the staging area, and commit it.
4. To create a pull request from this branch (as is good practice for pull requests): push it to your local fork: git push --set-upstream origin Wagner

Enumerating objects: 4, done.
Counting objects: 100% (4/4), done.
Delta compression using up to 8 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 305 bytes | 305.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0)
remote: 
remote: Create a pull request for 'Wagner' on GitHub by visiting:
remote:      https://github.com/adswa/git_intro/pull/new/Wagner
remote: 
To github.com:adswa/git_intro.git
 * [new branch]      Wagner -> Wagner
Branch 'Wagner' set up to track remote branch 'Wagner' from 'origin'.

5. Lets say you want to merge this branch into your master branch locally:

git checkout master
git merge Wagner

Here are a few git resources:

• a condensed summary of git principles and commands in our docs: https://docs.inm7.de/tools/git/
• The git cheat sheet: https://github.github.com/training-kit/downloads/github-git-cheat-sheet.pdf
• a well-made git tutorial: https://swcarpentry.github.io/git-novice/
• Pro git, a comprehensive book on everything git: https://git-scm.com/book/en/v2
• a game to learn branching with: https://learngitbranching.js.org/