Git in a nutshell

Git In a Nutshell

By: Pranesh Vittal CG http://in.linkedin.com/in/praneshvittal

Key takeaways from this session

•  Differences between Centralized & Distributed Version Control System.

•  Unlearning some of the concepts from CVS / SVN World. •  What is Git? •  Git IniEalizaEon •  Git Config / Git Ignore •  Most Frequently Used Git Commands •  Merging Conflicts •  Git Mergetool •  Git Help •  Git CollaboraEon Methods •  What is a PR and the steps associated with it?

What is SCM ???

SCM -‐> Source Control Management VCS -‐> Version Control System Centralized VCS

•  CVS, Perforce, SVN Distributed VCS

•  Git, Mercurial

Unlearning CVS & SVN

git equivalent for “svn checkout url” is “git clone url” git equivalent for “svn update” is “git pull” git equivalent for “svn commit” is “git commit -‐a && git push” Some of the features available in Git: •  Cheap & Easy Branching. •  Disconnected Use wherein the user is not connected to

the Network. •  Staging just what is required for a parEcular feature. •  BeYer collaboraEon with other developers.

What is Git ???

•  Distributed VCS •  Everything is check-‐summed (40 characters sha-‐1 hash. Hexadecimal unique value

calculated based on author’s name & email-‐id, contents of the file & few other parameters).

•  Snapshots and not differences. •  Everything related to the git project can be found in .git directory at the root level of

the project.

What is Git ???

•  Nearly Every AcEon Is Local. •  Consists of following areas:

–  Working Directory –  Staging Area –  Git Repository

In a nut shell

Git Config

•  git config -‐-‐global user.name “Pranesh ViYal” •  git config -‐-‐global user.email “[email protected]”

OR

•  ~/.gitconfig [user]

name = Pranesh ViYal email = [email protected]

[credenEal] helper = cache -‐-‐Emeout=3600

[core] editor = vim

[merge] tool = vimdiff

[alias] b = branch

•  More such examples : hYps://gist.github.com/pksunkara/988716

.giAgnore

# Compiled source # *.com *.class *.dll *.exe *.o# Logs and databases # *.log *.sql *.sqlite # OS generated files # .DS_Store* ehthumbs.db Icon? Thumbs.db

*.so # Temporary files # *.swp *.swo *~ # Packages # *.7z *.dmg *.gz *.iso *.jar *.rar *.tar *.zip

https://github.com/sethvargo/chefspec/blob/master/.gitignore

Most Frequently Used OperaAons

init add branch commit checkout diff fetch log merge

prune push pull rebase reset remote status stash show tag

Most Frequently Used Commands

•  git init (Arer creaEng the directory and cd into into it). •  git clone <git-‐repo> •  git add . (Add untracked files) •  git status (Current status of the local git directory). •  git commit -‐m “First Commit of the file.” (Commit the files).

•  git push <remote-‐short-‐name> <branch-‐name> (Push the changes to the repository).

•  git log (Log of checkins performed on the branch). •  git log -‐p -‐2 (Details of the last 2 commits). •  git log -‐-‐preYy=oneline (Log info in oneline format). *remote-‐short-‐name -‐ default value is origin

Most Frequently Used Commands •  git diff <old-‐tag> <new-‐tag> (Show changes between commits,

commit and working tree etc...) •  git diff -‐-‐cached (Diff between the working and the staged

area) •  git diff HEAD (Diff between the working and the repository) •  git rm -‐f <filename> (Delete the file from git). •  git reset HEAD <file-‐name> (To reset a file that has been

staged but not checked-‐in). •  git checkout <file-‐name> (To reset a file that has been been

modified in working area). •  git stash (Temporary check-‐in while switching between

branches). •  git stash list (List of stash items). •  git stash apply @stash@{n} (Add the stashed items back to the

branch).

Most Frequently Used Commands •  git branch (List the branches on the local repository. Can be found

in .git/refs/heads/). •  git branch new-‐branch (Create new branch). •  git checkout new-‐branch (Switch to the new branch). •  git checkout -‐b <new-‐branch> <remote-‐short-‐name>/<branch-‐

name> (To check out the new branch from the repository). •  git diff (Diff of the current state with the repository). •  git tag <tag-‐name> (To create a tag). •  git checkout -‐-‐track <remote>/<branch>

•  git branch -‐r (List the branches on the remote repository. Can be found in .git/refs/remotes/).

•  git branch -‐v (List out the recent commits performed in all the branches)

Most Frequently Used Commands

•  git remote (Display list of remote repositories). •  git remote add <remote-‐short-‐name> (To create a remote

repository). •  git remote fetch <remote-‐short-‐name> (To fetch the changes from

other repository.) •  git fetch <remote-‐short-‐name> (To get files from remote projects). •  git pull <remote-‐short-‐name> <branch-‐name> (AutomaEcally fetch

and then merge a remote branch into your current branch). •  git merge <branch-‐to-‐be-‐merged> (To merge the changes. Before

execuEng this, make sure that you are in the target branch). •  git rebase <branch-‐name> (FuncEons very similar to merge, but good

at keeping the history of changes in a clean way.) •  git branch -‐d <branch-‐name> •  git reset -‐-‐hard HEAD (When SHIT happens and you messed with too

many merges and you don’t care about the changes you did).

Merging Conflicts

git merge <branch-‐to-‐be-‐merged> Auto-‐merging index.html CONFLICT (content): Merge conflict in index.html AutomaEc merge failed; fix conflicts and then commit the result.

git status You have unmerged paths. <<<<<<< HEAD:index.html <div id="footer">contact : [email protected]</div> ======= <div id="footer"> please contact us at [email protected] </div> >>>>>>> iss53:index.html

git mergetool:

Git mergetool

Help !!!

git help <command> git help commit git help branch git help

Git Pull Requests

What is a pull request? Most important step wherein a collaborator sends across his changes to be merged into the master branch. The changes will be pulled by the commiYer and merged into the master.

Popular CollaboraAve Development Methods

•  Fork & Pull (Followed in most of the open source projects on GitHub).

•  Shared Repository Model (The one followed in in house projects)

Some of the popular models

References

hYp://nvie.com/posts/a-‐successful-‐git-‐branching-‐model/ hYp://scoYchacon.com/2011/08/31/github-‐flow.html hYp://git-‐scm.com/doc hYp://cleanercode.com/introducEon-‐to-‐git-‐talk/introducEon-‐to-‐git.pdf hYp://nvie.com/files/Git-‐branching-‐model.pdf

Q & A

Software

Git in a nutshell