Git primer

Version control with Git:

Git is a version control system that was created as a tool for Linux kernel development.
Today it is widely used in software industry and is also very popular in open-source projects.

Git consists of:

• Working tree
  • Is the name for file and folder structure that is being versioned.
  • Current directory contents
• Index / Stage / Cache
  • Staging area, where the new commit is prepared.
• Local repository
  • A local version of the repository where versions/commits are stored. You can actually find this information in .git folder that is hidden in the worktree's root.
• Remote repositories
  • a remote version of the repository. Remote repository is used to synchronise local repositories and store local version history to some remote location.
  • Your remote repository is called origin
  • The remote repository can be found from TUNI Course GitLab

Git tools

• The linux-desktop servers have Git installed
• You can run these commands in the terminal
• The FPGA lab TC217 computers have Git for Windows installed
• You can open the command line interface running Git Bash
• There is also a graphical TortoiseGit, that can be reached from the Windows Explorer context menu (right click)

Git commands required for this course:

0. Git settings

• To get started, give Git your name and email used for commits. Also set the text editor to more user-friendly nano if you're not used to vi:

$ git config --global user.name "Teemu Teekkari"
$ git config --global user.email "teemu.teekkari@tuni.fi"
$ git config --global core.editor nano 

1. Cloning your remote repository

• You can find your own cloning link in Course GitLab

$ git clone https://course-gitlab.tuni.fi/compce510-fall-2025/<GROUP_NUMBER>.git

2. Sharing your changes to the Remote repository (GitLab)

• When you want to publish and save your changed files to the Remote repository (GitLab):

1. Add all changed/new files to Index

$ git add .

2. Commit your changes in Index to Local repository

$ git commit -m "Message"

3. Push your new commits from Local repository to Remote repository

$ git push origin

3. Updating your Local repository and Working tree

• If someone, usually you on a different machine or your groupmate, has made changes to the Remote repository, you have to update the contents of your Local repository:

1. To update the changes made by others from the Remote repository

$ git pull origin

2. If you both have done changes in same files, it will lead to conflicts
• Resolve the conflicts by editing the files manually and commit your changes
• To prevent conflicts, pull the changes before editing files
• TortoiseGit has a nice editor for resolving the conflicts

4. Updating your Local repository and Working tree with updates done by the course staff

• From time to time, you have to get some new files from the course template repository:

1. Add the group template repository as new remote repository called course_upstream

$ git remote add course_upstream https://course-gitlab.tuni.fi/compce510-fall-2025/group_template_project.git

2. Fetch the new Remote repository to Local repository

$ git fetch course_upstream

3. Merge the changes to your Working tree

$ git merge course_upstream/main

Additional Git commands

• Show changes in Working directory after previous commit

$ git status

• Show commit history

$ git log

• Show all remotes

$ git remote -v

Additional Git terminology

• Branches are different history paths that diverge from the main line of development
• The default branch is called main
• HEAD is a pointer to the last commit made in the repository
• The current version of the project, as known by Git
• A commit represents one version of the project
• Each commit contains line-level changes to files compared to the previous commit
• Tags can be used to mark important points in project history
• For example release points (v1.0, v2.1 and so on)