This document provides an overview of version control systems and instructions for downloading and using Git. It explains that version control systems manage multiple versions of documents and projects. Git is a distributed version control system that treats all repositories as equal. The document then provides step-by-step instructions for installing Git, configuring user settings, cloning repositories from a school server, making changes to code and committing/pushing those changes to the repository, and resolving merge conflicts when changes cannot be automatically merged. It also lists some helpful Git commands.

1. Git
A distributed version control system
Powerpoint credited to University of PA
And modified by Pepper
5-Apr-23

2. Version control systems
 Version control (or revision control, or source control) is all
about managing multiple versions of documents, programs, web
sites, etc.
 Almost all “real” projects use some kind of version control
 Essential for team projects, but also very useful for individual projects
 Some well-known version control systems are CVS, Subversion,
Mercurial, and Git
 CVS and Subversion use a “central” repository; users “check out” files,
work on them, and “check them in”
 Mercurial and Git treat all repositories as equal
 Distributed systems like Mercurial and Git are newer and are
gradually replacing centralized systems like CVS and Subversion
2

3. Why version control?
 For working by yourself:
 Gives you a “time machine” for going back to earlier versions
 Gives you great support for different versions (standalone,
web app, etc.) of the same basic project
 For working with others:
 Greatly simplifies concurrent work, merging changes
 For getting an internship or job:
 Any company with a clue uses some kind of version control
 Companies without a clue are bad places to work
3

4. Download and install Git
 Tutorials
 Standard one: http://git-scm.com/downloads
 Here’s one from StackExchange:
http://stackoverflow.com/questions/315911/git-for-beginners-the-
definitive-practical-guide#323764
 Install Git on your machine from http://git-scm.com/downloads
 Accept context menu items
 Git access:
 Right click from windows explorer
 gitBash to enter commands
 Current local directory is folder you launched from
 Good idea - one folder for your git local access
4

5. Introduce yourself to Git
 Start git / gitBash
 See your options:
 git config -l
 Enter these lines (with appropriate changes):
 git config --global user.name "John Smith"
 git config --global user.email jsmith@seas.upenn.edu
 You only need to do this once
 If you want to use a different name/email address for a
particular project, you can change it for just that project
 cd to the project directory
 Use the above commands, but leave out the --global
5

6. Setting options
 When you “commit,” git will require you to type in a
commit message
 For longer commit messages, you will use an editor
 To change the default editor:
 git config --global core.editor /usr/bin/vim
 You may also want to turn on colors:
 git config --global color.ui auto
 See your options:
 git config -l
6

7. Clone repositories on panther
 Our repositories
 http://home.adelphi.edu/~pe16132/csc440/repositories.html
 Get the files from your repository before starting
 Make a local respository as a clone of master
 Make a new folder
 Right click the folder and choose git bash
 Type: git clone
ssh://pepper@panther.adelphi.edu/opt/git/csc480ASpring15.git
 Enter your ecampus password
 See all the contents of the folder
 Windows Explorer: Change folder and search options to show
hidden files, folders and drives
 Git Bash (unix) : ls -a to see the .git folder.
7

8. Using Gui to Clone repository
8
• Open git Gui
• Choose Clone Existing Repository
• Source: ssh://pepper@panther.adelphi.edu/opt/git/csc480ASpring15.git
• Target: New folder on your system
• Enter password 3 times

9. GitBash Changing your repositories
 Make changes
 See what changed
 git diff
 Stage changes
 git add –all (or particular files) note 2 dashes!
 git diff –cached (:q! to exit)
 Still only in your repository
 Put changes back up into repository
 Commit your staged changes in your repository
 git commit -m "the reason for the change"
 Update the respository:
 git push origin
9

10. GitGui Managing your Repositories
 Rescan to see changes to
stage
 Stage changed to say you
want to track those changes
 Click left box to unstage
 Sign off to start a commit
message text
 Commit - Enter reason first
 Push the changes up to the
repository
10

11. Viewing and Resetting repository
 See what is on the repository
 git remote
 ls to see files
 cd & cd .. to move around folders
 cat to see file contents
 vi to edit file contents and end with <esc> :wq
 Get what is on repository
 git pull
 If it says to resolve manually, just vi that file and see the head
which is yours
11

12. Failed Push
 When you don't have the latest copy it will fail:
12

13. Recover from failed push
 Copy your repository elsewhere first just in case
 Use git bash
 Git pull to pull down the changes
 Files needing merging will have both sets of text :
<<<<<<< HEAD
change once not pushed
=======
change once pushed
>>>>>>> d43e1181ce3d7d0ca45fe0d2ce1a6120def02c37
 Head is your local copy version
 Add --all ; commit and push again
13

14. Typical workflow
 git pull remote_repository
 Get changes from a remote repository and merge them into
your own repository
 git status
 See what Git thinks is going on
 Use this frequently!
 Work on your files
 git add –-all (or just changes)
 git commit –m “What I did”
 git push
14

15. Helpful gitBash commands
 Show staged differences: git diff -- cached
 Show status : git status
 Show branches: git branch
 See history: git log
 Checkout a branch: git checkout branch
 Fetch so you can look but maybe not take: git fetch
 Pull will fetch and merge with what you have: git merge
15

16. Git log commands
 git log
 --pretty=oneline --max-count=2 git log
 --pretty=oneline --since='5 minutes ago' git log
 --pretty=oneline --until='5 minutes ago' git log
 --pretty=oneline --author=<your name> git log
 --pretty=oneline –all
16

17. Git log pretty
 git log --pretty=format:"%h %ad | %s%d [%an]" --graph --
date=short
 --pretty="..." defines the output format.
 %h is the abbreviated hash of the commit
 %d commit decorations (e.g. branch heads or tags)
 %ad is the commit date
 %s is the comment
 %an is the name of the author
 --graph tells git to display the commit tree in the form of
an ASCII graph layout
 --date=short keeps the date format short and nice
17

18. Good aliases
 alias gs='git status '
 alias ga='git add '
 alias gb='git branch '
 alias gc='git commit'
 alias gd='git diff'
 alias go='git checkout '
 alias gk='gitk --all&'
 alias gx='gitx --all'
 alias got='git '
 alias get='git '
18