Git Cheat Sheet

A summary of my Git learnings, makes a handy cheat sheet.

April 20, 2022 by Tim Greenslade

Photograph of Octocat and Groot reading a book

Git Setup

Create directory mkdir
git init creates a local repository. It is done in an existing directory
$ git clone https://github.com/<directory> to clone a repository into the directory
git add
git commit
git push

git log Is used to display commits. It includes:

the SHA: a unique identifier for each commit (first 6-8 characters enough to search for specific one)
the author
the date
the commit message

git log --oneline cuts down SHA to 7 characters and only shows commit message

git log --stat displays additional information:

which files were modified
how many files were modified
how many lines added
how many lines deleted

git log -p (same as --patch flag) Shows information specific to what changes were made, you can see the following:

file that was changed
versions of the file a/ b/ etc.
which lines were changed @@ -40,6 - start line, how many lines were changed.
actual changes to the code are shown (green for added, red for removed)

-w To ignore whitespace changes.

git show Is used to search by a specific SHA

Adding Commits to Repo

git add used to move files into the staging index

git add index.html app.css js/app.js to move multiple items

git add . to move all files in current directory into staging index

git commit adds files to repository from staging index:

prompts editor to open requesting a commit message

enter, save and close the editor.

Result:

─tim@LAPTOP-7RMVA9J2 ~/udacity-git-course/new-git-project ‹master●›

        ╰─$ git commit

        [master (root-commit) 4f78fd3] Initial commit

        3 files changed, 14 insertions(+)

        create mode 100644 css/app.css

        create mode 100644 index.html

        create mode 100644 js/app.js

Editor can be skipped with git commit -m "Initial commit"

git diff shows changes that have been made but haven't been committed.

Git ignore

git ignore create .gitignore file and add files you want ignored into it.

Globbing you can add patterns/characters to .gitignore to avoid listing each file individually. Options:

blank lines can be used for spacing
        # - marks line as a comment
        * - matches 0 or more characters
        ? - matches 1 character
        [abc] - matches a, b, _or_ c
        ** - matches nested directories - a/**/z matches
            a/z
            a/b/z
            a/b/c/z

samples/*.jpg for example.

Commit rules

Each commit should record a single change(add a new image to the sidebar, change the header, add a carousel etc.)
Keep messages short and explain what the commit does, not how.
You shouldn't need to use the word 'and' as the commit should be singular.
Use the template "This commit will..." except, only type the sentences end.
Be consistent

If you need to add a description of why you made a commit do it in the Editor, 2 lines down from the commit message.

Also, describe changes in imperative:

Describe your changes in imperative mood, e.g. "make xyzzy do frotz" instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy to do frotz" as if you are giving orders to the codebase to change its behaviour. Try to make sure your explanation can be understood without external resources. Instead of providing a URL to a mailing list archive, summarize the relevant points of the discussion. - git.kernel.org

Navigating

Navigating The Log

If you're not used to a pager on the command line, navigating in Less can be a bit odd. Here are some helpful keys:

to scroll down, press
            j or ↓ to move down one line at a time
            d to move by half the page screen
            f to move by a whole page screen
        to scroll up, press
            k or ↑ to move _up_ one line at a time
            u to move by half the page screen
            b to move by a whole page screen
        press q to quit out of the log (returns to the regular command prompt)

Branch, Pull, Merge

git branch <name> to create a new branch
git checkout <branch name> to switch to branch.
git merge <branch name> merges branch with current branch.
git branch -d <branch name> to delete branches that aren't needed.
git checkout -b admin Creates a branch and checks it out.

When merging the Editor can come up asking if you want to change the merge message. Once you have changed it type :wq (write + quit)

make push request

when you want to add your branch to the main, you typically need someone to check it for you and merge. To set this up you need to make a pull request:

Push your branch up git push origin your-name
Create pull request by clicking new pull request
Share link https://github.com/dev-academy-foundations/ko-wai-koe/pull/830
Someone will merge the pull request after checking it and then delete the branch.
Check out main branch and pull down changes git pull

Fork and clone

Go to repository click fork
clone repository git clone <repo https>
configure Git to pull changes from original upstream repo into your local clone:

go to directory
git remote -v shows current remote repository for your fork:

origin https://github.com/YOUR_USERNAME/YOUR_FORK.git (fetch)

        origin https://github.com/YOUR_USERNAME/YOUR_FORK.git (push)

git remote upstream <https> to change remote repository
git remote -v

    origin  https://github.com/treegroves/Spoon-Knife.git (fetch)

        origin  https://github.com/treegroves/Spoon-Knife.git (push)

        upstream https://github.com/treegroves/Spoon-Knife.git (fetch)

        upstream https://github.com/treegroves/Spoon-Knife.git (push)

Make changes, add, commit and push
Go to your copy of the repo, you will see something like: This branch is 1 commit ahead of octocat/Spoon-Knife:main. To the right click contribute then open pull request
click create pull request and add a title and comment about the commit
click Create pull request
pull request page comes up copy and share url e.g. https://github.com/octocat/Spoon-Knife/pull/26747
This is a screenshot of the final window: