How to use git

This guide is sarcastic. Of course we all love git! git is very easy to use. You just have to learn 1024 different commands.

Basics

In order to install a project on your computer, open a terminal in the folder you put all your projects. Write

git clone 'address'

Whereever you want to work, open a terminal in the folder of your project. First, in order to get all the changes made by your colleagues, run git pull. Work locally as you are used to work. When you think that you made some progress that you want to stamp, run git commit -a -m "I added a new section". When you want to share all your committed work with your colleagues, run git push. In git the commit and the push phases are distinct, otherwise it would have been too simple.

For removing a file, simply remove it! That is may too complicated, they should have invented a special command for that, but no, this time, it is simple. For adding a file that you want git to keep track, run git add miaou.txt where miaou.txt is the file you want to add.

Git pull

Sometimes git pull is made difficult. Do you know why? Because git opens a vi interface! vi is a very super-easy intuitive text editor, and it is so obvious that quitting vi is by pressing Ctrl + XW (I think). git could have been coupled by default with another text editor, or could have embedded its own editor, but they preffered to choose the best super-easy intuitive text editor: vi.

Conflicts

Sometimes, the system indicates that you have made changes that differ from what your colleagues have done. In that case, do git pull before. Sometimes, there are conflicts meaning that you and some other colleagues worked on the same part of the project. Some file contains portions like:

`<<<<<<< HEAD`
    `what you have on your computer`
`=======`
   `what others have done`
`>>>>>>> cbc151ae7fa34600f830302e52d85d6109aab9c7`

(do not ask me what is cbc151ae7fa34600f830302e52d85d6109aab9c7, git should remain a bit obscure ;) )

In that case, just edit the files and keep the version of the lines you like. Remove the ugly lines <<<<<<< HEAD, ======= and >>>>>>> cbc151ae7fa34600f830302e52d85d6109aab9c7. Also, in order to solve conflicts, I strongly recommend to use Visual Studio Code for editing text files, because solving conflicts is as easy as clicking! In case of conflicts, if they are solved, simply do git commit -a -m "conflict solved" and git push. I do not know what happens if your file contains lines <<<<<<< HEAD, ======= and >>>>>>> cbc151ae7fa34600f830302e52d85d6109aab9c7 on purpose. It would be very interesting to know which lines are the real content of the files and which are the new lines inserted by git. Hum... no it is not interesting.

SSH keys

I think it is more convenient to work with SSH keys. The only thing is to know the magic command for creating your own SSH keys. Run ssh-keygen -t rsa -b 4096.

Branches

Branching is a nice mechanism, but its use is counterintuitively simple.

List the branch names

If you want to list the existing branches, but to branch, use git branch. Yes! git branch does not branch, otherwise the name of the command would have been to transparent. A command like "git list-branch" would have been too crystal clear.

Create a branch

To create a branch, do git branch <nameofmybranch>. (yes that is the same command... we could have imagined "git newbranch ..."). To move to a branch, we could have imagined "git changebranch ..." or "git gotobranch ...", but no.. it is git checkout <nameofmybranch>.

Merge

Suppose you have a branch called amazingfix and you want to include this amazing fix into the main branch master. Proceed as follows:

• goto branch master via git checkout master
• rappatriate the new amazing fix git merge amazingfix

Specific questions

How do I know what is the address of the repository?

Run git remote -v.

I changed the name of a repository on github. How do I say to my local folder the new address of the repository?

Run git remote set-url origin blablablabla where blablablabla is the address of the repository. For instance, run git remote set-url origin [email protected]:tableaunoir/tableaunoir.git.

How do I change messages in previous commit?

To change the message of the last commit, run git commit --amend -m "New commit message". Otherwise, read the manual because git is too user-friendly.

Error when push!

Sometimes, you push git push and you get:

error: src refspec refs/heads/master matches more than one error: failed to push some refs to '[email protected]:tableaunoir/tableaunoir.git'

These error messages are very explicit (joke). In clear, it usually means that a branch and a tag have the same name. Just delete/rename tag. You can rename/delete tags in the interface of github. Also, some releases may be generated so maybe a script is running and keeps generating some tag with the same name than a branch.