Git: Distributed Version Control System

This post documents some of the most essential and common Git commands for version control.

Introduction

Git is software for tracking changes in any set of files, usually used for coordinating work among programmers collaboratively developing source code during software development. Its goals include speed, data integrity, and support for distributed, non-linear workflows.

Local repository consists of three trees maintained by git.

1. Working Directory - holds the actual files.
2. Index - staging area.
3. HEAD - points to the last commit.

Goals

1. Initialization
2. Local Workflow
   2.1 Undo Changes
   2.2 Tagging
   2.3 Logs
   2.3 Branching
   2.3.1 Deleting a Branch
3. Remote Repository
   3.1 Pulling & Pushing Changes
4. Others

Minimum Software Requirements

• Git

1. Initialization

• git init
  Initializes a new git repository

• git clone /path/to/repository
  creates a working copy of a local repository

• git clone username@host:/path/to/repository
  creates a working copy of a remote repository

2. Local workflow

• git add <filename>
  add a single changed file to staging area (Index)

• git add *
  add all changed files to staging area (Index)

• git commit -m "Commit message"
  commits the changed files in staging area to HEAD

• git diff file-name.file_type
  See changes to a specific file using git

2.1 Undo all working dir changes including new files

Delete all changes from working directory including new untracked files.

• git reset --hard
  Removes staged and working directory changes

• git clean -nfd
  To see what will be deleted before-hand, without actually deleting it, use the -n flag (this is basically a test-run). When you are ready to actually delete, then remove the -n flag

• git clean -f -d
  Remove untracked

• git clean -f -x -d
  CAUTION: as above but removes ignored files like config.

• git clean -fxd :/
  CAUTION: as above, but cleans untracked and ignored files through the entire repo (without :/, the operation affects only the current directory)

Reference: https://stackoverflow.com/questions/1090309/git-undo-all-working-dir-changes-including-new-files

2.2 Tagging

• git tag 1.0.0 1b2e1d63ff
  create a new tag named 1.0.0 where 1b2e1d63ff stands for the first 10 characters of the commit id you want to reference with your tag

• git tag -a 'Version_1_0' -m 'Simple UI' HEAD
  Create Tag - Tag operation allows giving meaningful names to a specific version in the repository.

• git push origin tag Version_1_0
  push the tag into the remote repository

• git tag -l
  view all the available tags

2.3 Logs

• git log
  displays repository commit history

• git log --author=bob
  displays only the commits of a certain author

• git log --pretty=oneline
  displays a very compressed log where each commit is one line

• git log --graph --oneline --decorate --all
  displays an ASCII art tree of all the branches, decorated with the names of tags and branches

• git log --name-status
  displays only which files have changed

• git log --pretty="- %s" > CHANGELOG.md
  save changelog to file.

• git log --oneline --decorate
  output with one commit per line.

• git log --pretty="%C(Yellow)%h %C(reset)%ad (%C(Green)%cr%C(reset))%x09 %C(Cyan)%an: %C(reset)%s"

• git log --all --decorate --oneline --graph

• git log --pretty="- %s"

• git log --oneline -5 --author JohnDoe --before "Fri Mar 26 2009"

2.4 Branching

1. Branches are used to develop features isolated from each other.
2. main/master branch is the default branch in a repository.
3. other branches are used for development and merged back to the main/master branch upon completion.

• git checkout -b feature_x
  create a new branch named feature_x and switch to it using

• git checkout master
  switch back to master branch

• git push origin <branch>
  push from local to remote branch

• git push --all origin
  Push all branches to your remote repository

2.4.1 Deleting a branch

• git push -d origin <branch name>
  Remove a remote branch from the server

• git branch -d <branch name>
  Delete local branch

3. Remote Repository

• git remote add origin <server>
  If you have not cloned an existing repository and want to connect your repository to a remote server.

• git remote set-url origin https://github.com/user/new-repo.git
  Change the URI (URL) for a remote Git repository

• git remote show origin
  Find the URL of the remote repository.

• git remote -v
  List all currently configured remote repositories

3.1 Pulling and Pushing changes

• git pull
  update your local repository to the newest remote commit.

• git push origin <branch>
  push the changes to your remote repository.

4. Others

• git log --help
  opens a local git-log manual (html) page

• gitk
  opens a built-in git GUI desktop application

Tags

• Git