This document provides an overview of version control systems and instructions for downloading, installing, and using the distributed version control system Git. It explains the basics of Git including configuring user information, choosing an editor, interacting with remote repositories, and common commands for viewing changes, staging files, committing changes, and viewing the commit history. Typical workflows and some helpful formatting options for the git log command are also demonstrated.

1. Git
A distributed version control system
Powerpoint credited to University of PA
And modified by Pepper
31-Jul-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
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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
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4. Download and install Git
 There are online materials that are better than any that I could
provide
 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
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5. Introduce yourself to Git
 Start git / gitBash
 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
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6. Choose an editor
 When you “commit,” git will require you to type in a
commit message
 For longer commit messages, you will use an editor
 The default editor is probably vim
 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
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7. Your repositories
 We have created 6 class repositories on panther, and
here are their paths.

ssh://user_name@panther.adelphi.edu/opt/git/csc271books.git

ssh://user_name@panther.adelphi.edu/opt/git/csc271tv.git

ssh://user_name@panther.adelphi.edu/opt/git/csc271store.git

ssh://user_name@panther.adelphi.edu/opt/git/csc271movies1.git

ssh://user_name@panther.adelphi.edu/opt/git/csc271games1.git

ssh://user_name@panther.adelphi.edu/opt/git/csc271movies2.git

Prior class: csc440Spring14r1

Use instructions to follow
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8. Using your repositories on panther
 Get the files from your repository before starting
 Make a local respository as a clone of master
 git clone /opt/git/csc271books
 See all the contents of the folder
 ls -a to see the .git folder.
 Make changes
 See what changed
 git diff
 Stage changes
 git add –all (or particular files)
 git diff –cached
 Still only in your repository
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9. Using 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
 See what is on the repository
 git remote
 Get what is on repository
 git pull
 If it says to resolve manually, just vi that file and see the head
which is yours
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10. 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
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11. 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
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12. 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
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13. 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
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14. 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 '
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