Git

1
Git

• A distributed version control system
• Powerpoint credited to University of PA
• And modified by Pepper

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

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

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
• Heres one from StackExchangehttp//stackoverflo
  w.com/questions/315911/git-for-beginners-the-defin
  itive-practical-guide323764
• 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

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_at_seas.upenn.e
  du
• 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

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

7
Your repositories

• We have created 6 class repositories on panther,
  and here are their paths.
• ssh//user_name_at_panther.adelphi.edu/opt/git/csc271
  books.git
• ssh//user_name_at_panther.adelphi.edu/opt/git/csc271
  tv.git
• ssh//user_name_at_panther.adelphi.edu/opt/git/csc271
  store.git
• ssh//user_name_at_panther.adelphi.edu/opt/git/csc271
  movies1.git
• ssh//user_name_at_panther.adelphi.edu/opt/git/csc271
  games1.git
• ssh//user_name_at_panther.adelphi.edu/opt/git/csc271
  movies2.git
• Prior class csc440Spring14r1
• Use instructions to follow

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

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

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

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

12
Git log commands

• git log
• --prettyoneline --max-count2 git log
• --prettyoneline --since'5 minutes ago' git log
• --prettyoneline --until'5 minutes ago' git log
• --prettyoneline --authorltyour namegt git log
• --prettyoneline all

13
Git log pretty

• git log --prettyformat"h ad sd an"
  --graph --dateshort
• --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
• --dateshort keeps the date format short and nice

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 '