Git A distributed version control system Powerpoint credited

Git A distributed version control system Powerpoint credited to University of PA And modified by Pepper 31 -Oct-20

Version control systems n Version control (or revision control, or source control) is all about managing multiple versions of documents, programs, web sites, etc. n n n Some well-known version control systems are CVS, Subversion, Mercurial, and Git n n n Almost all “real” projects use some kind of version control Essential for team projects, but also very useful for individual projects 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

Why version control? n For working by yourself: n n n For working with others: n n 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 Greatly simplifies concurrent work, merging changes For getting an internship or job: n n Any company with a clue uses some kind of version control Companies without a clue are bad places to work 3

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

Introduce yourself to Git n n Start git / git. Bash See your options: n n Enter these lines (with appropriate changes): n n git config -l 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 n n cd to the project directory Use the above commands, but leave out the --global 5

Setting options n n n 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: n n You may also want to turn on colors: n n git config --global core. editor /usr/bin/vim git config --global color. ui auto See your options: n git config -l 6

Clone repositories on panther n Our repositories n n http: //home. adelphi. edu/~pe 16132/csc 440/repositories. html Get the files from your repository before starting n Make a local respository as a clone of master n n Make a new folder Right click the folder and choose git bash Type: git clone ssh: //pepper@panther. adelphi. edu/opt/git/csc 480 ASpring 15. git n Enter your ecampus password See all the contents of the folder n Windows Explorer: Change folder and search options to show hidden files, folders and drives n Git Bash (unix) : ls -a to see the. git folder. 7

Using Gui to Clone repository • • • Open git Gui Choose Clone Existing Repository Source: ssh: //pepper@panther. adelphi. edu/opt/git/csc 480 ASpring 15. git Target: New folder on your system Enter password 3 times 8

Git. Bash Changing your repositories n Make changes n See what changed n n Stage changes n n git diff 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 n Commit your staged changes in your repository n n git commit -m "the reason for the change" Update the respository: n git push origin 9

Git. Gui Managing your Repositories n n Rescan to see changes to stage Stage changed to say you want to track those changes n n 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

Viewing and Resetting repository n See what is on the repository n n n 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 n n git pull If it says to resolve manually, just vi that file and see the head which is yours 11

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

Recover from failed push n n 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 >>>>>>> d 43 e 1181 ce 3 d 7 d 0 ca 45 fe 0 d 2 ce 1 a 6120 def 02 c 37 n n Head is your local copy version Add --all ; commit and push again 13

Typical workflow n git pull remote_repository n n git status n n n Get changes from a remote repository and merge them into your own repository 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

Helpful git. Bash commands n n n n 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

Git log commands n git log n n n --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

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

Good aliases n n n n n 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