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Git

  • It is a type of Distributed Version Control Systems
    • clients fully mirror the repository and history
    • if any server dies, the client repositories can be copied back up to the server to restore it
      • only if the systems were collaborating via that server
    • every clone is a full backup of all the data
  • It is better than the Centralized Version Control Systems
    • file is stored and modified in the server
    • clients can view or modify the file if authorized by the administrator
    • problem is if server is down, no one can view or modify the file
  • It is better than the Local Version Control System
    • file is stored and modified locally
    • problem is it is error prone (ex: save or copy wrong file)

Set config values​

  • git config --global user.name "My Name" let collaborators know who modified the source code
  • git config --global user.email "myemail@email.com" let collaborators know the email of the person who modified the source code
  • git difftool --tool=<toolName> set external graphical diff viewing program
  • git config --global init.defaultBranch main set default branch name as "main" instead of master

View config values​

  • git config --list

Get help for git commands​

  • git help <verb> or git <verb> --help

Initialize a repository from existing code​

  • git init creates a .git folder to track changes

View current status of repository​

  • git status

Ignore files to prevent it from being tracked by git​

  • Create a .gitignore file if it does not exist
  • Write the filename or folders to ignore in the file
    • .DS_Store add file
    • *.pyc add all file that end with .pyc
    • !test.pyc track test.pyc even though all files that end with .pyc is to be ignored
    • /filename ONLY ignore this file in the current directory and not in other directories
    • folderName/ ignore all files in with this folderName

Git stages​

  • Newly created or recently modified files are in the "working directory"
  • Files can only be committed if recent file changes are transferred from the "working directory" to the "staging area"
  • When files are committed, the files are transferred from the "staging area" to the ".git directory"

Add new file or recently modified file to the "Staging area"​

  • git add <filename>
  • git add -A stages all changes (new files, modified files, deleted files)
  • git add . (version 1.x) stages new files and modified files only, (version 2.x) stages ALL changes
  • git add --ignore-removal . stages new files and modified files only (only in version 2.x)
  • git add -u stages modified files and deleted files only

Remove file from "Staging area"​

  • git reset <filename> unstage file from the staging area (unstaged change will NOT be displayed in the history)
  • git rm --cached <filename> stages the file's removal from the staging area
    • git rm <filename> WARNING: this will actually delete the file from the system and stage the file's removal
  • git reset remove all files from staging area
  • git reset --hard <shortRepoName>/<branchName> discards all history and changes back to the specified commit git reset --hard origin/master

Reference branch HEAD to different commit​

  • git branch -f <branchName> <commit>

Rename or move file then add to the "Staging area"​

  • git mv <oldFilenameOrWithPath> <newFilenameOrWithPath>

Unmodify file​

  • git checkout -- <filename> revert modified file to the last commit

Commit files from the "Staging area" to the ".git directory"​

  • git commit an editor will open to allow you to write the commit changes message
  • git commit -m "message about the changes made" write the commit changes message directly in the terminal
  • git commit --amend undo and recommit new changes (ex: add forgotten files, modify commit messages)

Edit specific commit contents and message​

  • git rebase -i '<commit>^'
    • the ^ will ensure the latest commit will be taken into consideration
    • after entering the command, a help menu will be displayed in the text editor and you need to change the specific commits to the desired command

Add and commit​

  • git commit -a "-a" adds all new and modified files and open an editor for comments
  • git commit -am "message about the changes made" adds all new and modified files with comments on 1 line

Undo commit​

  • git revert [saved hash] git will create a new commit that undoes that commit

View git history​

  • git log
  • git log --pretty=oneline or git log --oneline display one line logs
  • git log --graph display logs with ASCII graph showing the branch and merge history

Stashing to put untracked or staged files into a temporary space​

  • remove from current commit and store at a temporary space
    • git stash
  • put back untracked or staged files to commit
    • git stash pop

Cloning a remote repository​

  • git clone <gitURL> <whereToClone>

View remote information about the repository​

  • git remote -v

Add remote repositories​

  • git remote add <shortRepoName> <url> shortRepoName is usually named as "origin"

Inspect a remote repository​

  • git remote show <shortRepoName>

Rename remote repository​

  • git remote rename <oldShortRepoName> <newShortRepoName>

Remove remote repository​

  • git remote remove <shortRepoName>

View all branches information in the repository​

  • git branch -a or git branch

View the differences of recently modified files in the "working directory" compared to the last commit​

  • git diff does not work on files that are already added to the "Staging area" or ".git directory"
  • git diff --staged or git diff --cached view differences for files in the "Staging area" compared to the last commit
  • git difftool -y change diff to difftool to use external program, add "-y" to agree to launching the external program

Create new branch​

  • git branch <newBranchName>

Rename current branch name​

  • git branch -m <newBranchName>

Change to a different branch​

  • git checkout <branchName>

Create and change to the new branch​

  • git checkout -b <newBranchName>

Delete branch​

  • git branch -d <branchName>
  • git push origin --delete <branchName> delete branch from remote repository

Merge branch with current master​

  • git merge <branchName>

Fetch data from the server but do not merge with your client​

  • git fetch <nameOfRemoteRepository> <branchNameThatWeWantToGet>

Fetch data from the server AND merge with your client​

  • git pull <nameOfRemoteRepository> <branchNameThatWeWantToGet> usually use git pull origin master

Update server from the client​

  • git push <nameOfRemoteRepository> <branchNameThatWeWantToSend> usually use git push origin master
  • git push -u origin <branchName> -u is required when pushing the branch for the FIRST time

Repositioning commits to the latest​

  • git rebase master when this is called at branch, it will reposition the branch commits to the latest master commits rebaseMaster
  • git rebase <branchName> when this is called at master, it will merge the branch commits as new commits rebaseBranch
  • AFTER rebasing, must do a git push -f
    • do NOT do just git push