Introduction to Git

Sign-up for GitHub.com

Create a repository (repo)

GitHub create a repo

Basic Git commands

[Windows, Linux & Mac]

git

git help tutorial

git command	Definition
clone	Clone a repository into a new directory
init	Create an empty Git repository or reinitialize an existing one
add	Add file contents to the index
status	Show the working tree status
commit	Record changes to the repository
fetch	Download objects and refs from another repository
pull	Fetch from and integrate with another repository or a local branch
push	Update remote refs along with associated objects

Command Prompt/Terminal

Configure Git

[Windows, Linux & Mac]

Highly suggest to keep your email private and use the one GitHub provides you.

git config --global user.name "Your Name Comes Here"
git config --global user.email [email protected]

Make VsCode default editor

[Windows/WSL, Linux & Mac]

git config --global core.editor "code --wait"

Saving your GitHub password with Git

wincred (GUI)

[Windows]

git config --global credential.helper wincred

Cache

[Windows, Linux & Mac]

Turn on the credential helper so that Git will save your password in memory for some time. By default, Git will cache your password for 15 minutes.

Set git to use the credential memory cache

git config --global credential.helper cache

To change the default password cache timeout

Set the cache to timeout after 1 hour (setting is in seconds):

git config --global credential.helper 'cache --timeout=3600'

Make a directory to host your repository

[Windows]

mkdir Repository\CosFNL\GitIntro

[Linux & Mac]

mkdir -p ~/Repository/CosFNL/GitIntro

[Windows]

cd Repository\CosFNL\GitIntro

[Linux & Mac]

cd Repository/CosFNL/GitIntro/

[Windows, Linux & Mac]

git init

Initialized empty Git repository...

git add Readme.md

git commit -m "First commit"

[main (root-commit) 873e7b8] First commit
1 file changed, 117 insertions(+)
create mode 100644 Readme.md

git remote add origin https://github.com/CosFNL/GitIntro.git
git push -u origin main

Enumerating objects: 3, done.
Counting objects: 100% (3/3), done.
Delta compression using up to 8 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 1.21 KiB | 1.21 MiB/s, done.
Total 3 (delta 0), reused 0 (delta 0)
remote:
remote: Create a pull request for 'main' on GitHub by visiting:
remote:      https://github.com/CosFNL/GitIntro/pull/new/main
remote:
To https://github.com/CosFNL/GitIntro.git
* [new branch]      main -> main
Branch 'main' set up to track remote branch 'main' from 'origin'.

Using Git for collaboration

Git Download

⭐Resources

• Pro Git Book
• Git Notes For Professionals

Connect to COS FNL repository

https://github.com/CosFNL/GitIntro.git

.ssh key

SSH Key

Add SSH Key to GitHub

Generating a new SSH key

Paste the text below, substituting in your email address.

ssh-keygen -t ed25519 -C "<em>[email protected]</em>"

Note: If you are using a legacy system that doesn't support the Ed25519 algorithm, use:

ssh-keygen -t rsa -b 4096 -C "[email protected]"

Make sure you're running PowerShell as an Administrator

Set-Service ssh-agent -StartupType Automatic
Start-Service ssh-agent
Get-Service ssh-agent

Advanced Git commands

Branching & Merging

[Windows, Linux & Mac]

This workflow is primary branching and merging to prevent code loss and help with development vs. production workflows.

iss53 is the new branch we want to work with.

git checkout -b iss53

Shorthand for

git branch iss53
git checkout iss53

Make your changes to the file and commit them.

git commit -a -m 'Finish making x change'

Merge the changes back to main branch

git checkout main

Switched to branch 'main'
Your branch is up to date with 'origin/main'.

git merge iss53

Updating e46f478..20c8f8b
Fast-forward
Readme.md | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)

Delete iss53 branch

git branch -d iss53

Reset/Revert

If you made a mistake and need to revert to the previous commit. Avoid doing HARD reset and always create a new branch when working on a project to prevent major issues.

git command	Definition
log	Show commit logs
reflog	Manage reflog (reference logs) information
reset	Reset current HEAD to the specified state

Command Prompt/Terminal

reflog - referance logs

The reflog will list the reference commit headers, which will use to revert or reset the project.

[Windows, Linux & Mac]

Show the HEAD logs with one line with basic graph pointers. Play around with the various options to see what suits your workflow.

git log --oneline --graph

Git reset options

git reset options	Definition
--soft	Does not touch the index file or the working tree at all (but resets the head to <commit>, just like all modes do). This leaves all your changed files "Changes to be committed", as git status would put it.
--mix	Resets the index but not the working tree (i.e., the changed files are preserved but not marked for commit) and reports what has not been updated. This is the default action.
--hard	Resets the index and working tree. Any changes to tracked files in the working tree since <commit> are discarded.

Git HEAD - ref that points to the tip (latest commit) of a branch.

Git hard Reset HEAD Options

(Going back to HEAD)

git reset --hard HEAD

(Going back to the commit before > HEAD)

git reset --hard HEAD^

(Equivalent to "^")

git reset --hard HEAD~1

(Going back two commits before HEAD)

git reset --hard HEAD~2

Example

Let's revert to a particular HEAD ref of f6e5064 from our current head 3303307.

git reset --hard f6e5064

NOTE: Git only garbage collects after a month (by default). So you can recover your files if a --hard reset was done on the same machine.

Example

We lost files from f6e5064 due to hard reset. Going back to >3303307

git reset --hard 3303307

TODO: Finish this repo...