Version Control/Git

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Git is a distributed revision control software used by many open source projects. This learning resource is meant to help students learn to use it so that they can collaborate with other participants on software projects at Wikiversity.

Readings[edit]

Multimedia[edit]

  1. YouTube: Introduction to Git
  2. YouTube: Git Tutorial Series (25 videos)

Terms[edit]

  • Version control: The act of tracking the changes made by one or more users on a set of files
  • Remote repository: A directory of files tracked by a version control software on a server, usually accessed via the internet
  • Clone: To make a local copy of a remote repository
  • Branch: A set of deviations from a particular state of the repository
  • Merge: The act of combining two branches into a single one
  • Pull: To update a local repository with the latest changes from a remote repository
  • Push: To update a remote repository with the latest changes from a local repository

Activities[edit]

Git Installation[edit]

  • Windows: Download and install Git from https://git-scm.com/downloads.
  • MacOS: brew install git
  • Debian-based Linux: apt-get install git
  • Arch-based Linux: pacman -S git

Copy an existing remote repository[edit]

  1. Clone a remote repository.
    • Select a local folder to copy the repository into, or create a new folder if you prefer. The repository will be copied as a subdirectory of the selected folder.
    • At a command or terminal prompt, navigate to the selected folder.
    • Clone the repository using the command:
      git clone URL_TO_REPO. See also: git pull and git fetch

Create a local repository[edit]

  1. Initialize a folder for Git.
    • Select a local folder to add to Git, or create a new folder if you are starting a new project.
    • At a command or terminal prompt, navigate to the selected folder.
    • Initialize the folder using the command:
      git init

Make Local Changes and Update remote Repositories[edit]

Add local changes.

  1. Stage files.
    • Add files to the folder or modify existing files.
    • Add new and modified files to the git staging area using the command:
      git add .[1] or git add some_modified_file.txt or git add -A
  2. Commit changes.
    • Commit changes into the local repository using the command:
      git commit -m "<some message>"
  3. Connect to a remote repository.
    • Connect to a remote repository using the command:
      git remote add <name> <url>[2]
  4. Push changes to a remote repository.
    • Push changes from your local repository to a remote repository using the command:
      git push[3] or git push origin master or git push -h origin master

Retrieve Remote Changes[edit]

  • Pull/get changes from a remote repository to have latest version of the code
    • Pull/get changes from a remote repository to your local repository using the command:
git pull or git pull <name> <branch>
git pull -v (for more verbose output)
git fetch
gfind $1 -name ".git" | gsed -r 's|/[^/]+$||' | parallel "echo {}; git -C {} pull" (git pull all your repos in parallel, MacOS version)
  • Pull subdirectories:
ls | parallel git -C {} pull (assuming all sub-dirs are git repositories)[4]
ls | parallel git -C {} fetch
-C <PATH> run as if git was started in <path> instead of the current working directory.

Repository information[edit]

  • git remote -v or git remote show origin or git config --get remote.origin.url[5]

Git log[edit]

  • git log --oneline
  • git log --pretty=format:"%h - %an, %ar on %cd: %s"
  • Show modifications to a file:git log --follow -p FILE_TO_SHOW[6] or git blame FILE_TO_SHOW
  • git shortlog
  • List developers: git shortlogs -sne[7]

Git show[edit]

  • git show 3c88ad72430

Tags / Releases[edit]

  • Show all tags in git log:[8] git log --no-walk --tags --pretty="%h %d %s" --decorate=full
  • git tag (show releases)
  • List tags with dates: git log --tags --simplify-by-decoration --pretty="format:%ci %d"[9]. Just can also add taglog = log --tags --simplify-by-decoration --pretty='format:%ci %d' (note the single-, NOT double-quotes) in the [alias] section of your .gitconfig file.

Miscelaneous[edit]

  • git log --decorate=full --simplify-by-decoration
  • Print lines matching a pattern:git grep TEXT_TO_SEARCH
  • git merge[10]

Tips and Tricks[edit]

  • To avoid using --pager in all git log commands, add the following line to your ~/.bash_profile file:[11]
    export GIT_PAGER=cat


Activities[edit]

  1. Clone some public repositories
  2. Learn what is a merge or pull request: https://stackoverflow.com/questions/23076923/what-is-a-merge-request
  3. Create your first website in GitHub/Website Hosting using git
  4. Read StackOverflow questions about Git: https://stackoverflow.com/questions/tagged/git?tab=Votes

See Also[edit]

References[edit]