Git Cheatsheet

Quick reference on Git usage for RangeShifter contributors

Creating a local copy of this repo

git clone https://github.com/RangeShifter/RScore.git

Enquire about the current state of changes

git status

This will display whether the local branch is up-to-date with its GitHub counterpart, what files have been changed and if they are staged for commit or not.

Updating the active branch with latest changes (pulling)

git pull

Updating the active branch with another branch (merging)

git merge <branch to get new changes from>

Merging may trigger a merge conflict is the same lines have been changed on both branches. See Solving Merge Conflict below.

Staging changes to be committed

Changes to local files must first be added to the commit queue ("staged") before being committed.

git add <name of file> # single file
git add . # entire active folder

Creating a commit

git commit -m "commit message"

A good commit message is concise, but descriptive.

Uploading local commits to GitHub (pushing)

git push

Switching to an existing branch

git checkout <branch name>

Switching does not update the new active branch with GitHub automatically, so make sure to pull after switching!

Creating a new branch from active branch

git branch <name of new branch>

You will also need to set the corresponding branch on origin (GitHub) before you can push:

git push --set-upstream origin <name of branch>

New branches can also be created on GitHub (drop-down button in the top-left corner of the main page). New branches on GitHub are brought to the local copy with the next pull.

Deleting a branch locally

git branch -d <name of branch>

Instruct Git to not track some files

Open .gitignore and add the path to the files or folders to exclude from the git history. Check with git status that the files are indeed not tracked by git anymore.

Solving a merge conflict

Merge conflicts can arise when multiple contributors simulatneously change the same line of code. In such cases, git is incapable of deciding which version should be kept and asks for human input. Git tells you which files are affected by the conflict. Open each file and resolve each section that looks like this:

After opening the box, we can affirm that
<<<<<<<<<<< HEAD               # delete this line
Shroedinger's cat is alive.    # delete either this...
================               # delete this line
Shroedinger's cat is dead.     # ... or this (or keep both, or none, or a different solution)
>>>>>>>>>>> SHA                # delete this line
What an insightful result!

Ctrl+F "HEAD" is really helpful for finding the conflicts in large files. When you are done, create a commit stating e.g. "solved merge conflict" and push.

Git subtrees

See Git subtrees section in README.