git Cheatsheet

Command line basics

Developing some familiarity with the command line will come in very handy.

pwd: print the path of the directory you are in
cd PATH: change to the directory at a given PATH
cd: without a PATH cd takes you to your home directory
rm PATH: delete a file
rm -r PATH: delete a folder (the 'r' stands for recursive)
cp SOURCE DESTINATION: copy a file
cp -r SOURCE DESTINATION: copy a folder
mkdir PATH: create an empty folder
mv SOURCE DESTINATION: move a file or folder

When using paths on the command line you will come across some conventions.

.: a single dot is the current directory
..: two dots is the containing directory
~: a tilde is your home directory e.g. /home/alice (Linux etc.) or /Users/bob (Mac OS)
/: any path starting with a forward slash will be referring to the root of our entire filesystem

So given a file path of /home/alice/Desktop/code/2024-zebrafish-plots if you are in the Desktop you could move into the plots directory in many different ways:

cd /home/alice/Desktop/code/2024-zebrafish-plots
cd ~/Desktop/code/2024-zebrafish-plots
cd ./code/2024-zebrafish-plots
cd ../alice/Desktop/code/2024-zebrafish-plots
cd ./code/../code/../code/../../Desktop/code/2024-zebrafish-plots

The last is very silly on purpose to show you relative path movements.

You will come across the concept of absolute and relative file paths.

/home/alice/Desktop/code/2024-zebrafish-plots: an absolute file path as it starts at the root of the filesystem
/home/alice/Desktop/code/2024-zebrafish-plots: an absolute file path as it starts at the root of the filesystem

Setting up git

Installing git

To install git follow the official instructions for your operating system:

Linux/Unix
macOS (I recommend using homebrew)
Windows (if I had to use Windows I'd probably use WSL so that I had access to Linux tooling)

Basic git configuration

If you haven't used git on your computer before.

git config --global user.name "FIRSTNAME LASTNAME"
git config --global user.email "YOUR-EMAIL"

Whenever you make a commit your name and email are used for the 'author' metadata.

You can also run the following to make git command output easier to read.

git config --global color.ui auto

Using version control

Starting from scratch

Inside the folder you want to version control: git init

This will create the hidden .git directory that git uses as storage.

Cloning an existing repository

Cloning creates a copy of an existing repository on your machine. Depending on the address you use when cloning it will use a different form of authentication.

git clone git@github.com:erkannt/crop-and-rotate.git: This will use SSH key based authentication
git clone https://github.com/erkannt/crop-and-rotate.git: This will use username/password based authentication

Committing changes

The workflow is always:

make your changes
stage the changes you want to commit
commit your changes with a message

git add .: stage all of your changes
git add PATH: stage only the changes inside PATH
git add -p: interactively stage files or parts of files
git commit -m "MESSAGE": commit staged changes with MESSAGE
git commit: opens a text editor for you to write your commit message before committing
git restore PATH: discard changes to a specific file
git restore --staged PATH: un-stage a change (does not discard the change)
git reset --hard: discards all changes you have made since the last commit

Viewing state and history

There are a variety of ways to see what has happened in the past and what your current state is.

git status: shows you what you have changed and staged (if in doubt run this)
git log: see a history of your commits
git log --graph --oneline --decorate --branches --all: a compact view of history
git diff: see your current changes
git show: see the changes the last commit made
git show SHA: see the changes a specific commit made
(you can find the SHA by using git log)