KotlinPractice

Git Commands : Day-1

What is VCS. Why we need VCS.

VCS features.

GIT Installation (Ubuntu): $ sudo apt-get update $ sudo apt-get install git

Verify Installation: which git git --version

GIT Uninstallation: $ sudo apt-get remove git

Git Architecture Diagram - Centralized VCS - Ex: CVS/SVN/Clearcase/Perforce - Distributed VCS - Ex: GIT/Bitkeeper

Day-2

Creating remote repository in github

create an account in github.com URL: https://github.com
login github.com with your credentials. click on "new repository" --> give a name "flipkart-ecomerce" --> "create reopository"
copy the repo URL from Github: https://github.com/nageshvkn/flipkart-ecomerce.git
Clone the source code from remote repository using 'git clone' command git clone https://github.com/nageshvkn/flipkart-ecomerce.git
cd "flipkart-ecomerce" and observe ".git" folder. ".git" is called as "Local Reposiotory".
Create some sample code and submit the code to remote repo. --> touch Login.java --> git add Login.java --> git commit Login.java -m "login module code" --> git push

--> git log Login.java

Git Commit structure User/Email Timestamp Commit message

SHA / Version / Revison

Setting up mandatory configurations:

$ git config --global user.name "Nageswara Rao P" $ git config --global user.email "nageshvkn@gmail.com"

$ git config --global credential.helper cache

Check the configurations using below command $ git config --list

Git stores all configurations in below file "/home/gamut/.gitconfig"

Day-3

Understand Git Jargon.

- Remote Repository
- Working Directory
- Local Repository
- Stage/"Staging Index"

Skip staging

git commit -am "submit all pending changes"

Note: If you want to skip the staging, you need to commit all pending changes.

Creating up Local repository

create/initialize a local repository with 'git init' command $ git init gamutkart
Observe the local repository ls -a (you can see the .git folder. this is called the "local repository")

create some source code.. ex: vim Login.java

Adding the file to STAGE. $ git add Login.java

Commiting the file to local repository $ git commit Login.java -m "lgoin module code"

Check the log of Login.java using log command. $ git log Login.java

Day-4

History - Deep Dive

$ git log Login.java
$ git log

Options:
	- git log -n2
	- git log --author="nageshvkn"
	- git log --since="2016/12/13"
	- git log --until="2016/12/13"
	- git log --grep="DB code"		
	- git log --oneline

#Qn. Show me all logs committed by user "Ram" AND has a commit message "math function" in it.

$ git log --author="Ram" --grep="math function"

Day-5

GIT Commands

git diff Login.java

git diff --staged Login.java

git diff 089871935..fc894a6bf6d2e

Deleting a file

A.) git rm OMS.java git commit OMS.java -m "comment"
Renaming a file/folder A.) git mv Login.java Login1.java git commit -m "rename Login"

Git will carry the history of old file to new file. Use --follow option to see complete history. $ git log --follow Login.java

Day-6

BRANCHING

A. What is a branch?
B. Why and When we create a branch?
C. Branching Stratogy overview

List all the branches

$ git branch

Creating a new branch

$ git branch dev_1.2.3

Push new branch to remote repository

$ git push --set-upstream origin dev_1.2.3

Switching from one branch to another

$ git checkout dev_1.2.3

Creating and switching to a newly created branch

$ git checkout -b dev_1.2.4

How do you clone a single branch from remote repository

$ git clone -b dev_1.2.4 --single-branch https://github.com/nageshvkn/flipkart899.git

List all remote branches

$ git branch -r

HEAD

HEAD is a pointer in git which - Always points to the latest commit in the repository - Always points to tip of the current reposiotory - Always points to parent of the next commit

Day-7

Undoing the changes:

undo/revert local changes from source area $ git checkout -- LoginWeb.java

Unstage the changes from STAGE area $ git reset HEAD LoginWeb.java

Show all the files with content difference that are modified as part of a commit

git show git show b85a6e123

List only files that are committed as part of a revision.

$ git diff-tree --no-commit-id --name-only -r 41a7c2a456a

Day-8

Merging:

FAST-FORWARD MERGE

BEFORE MERGE:

		master
		 |

----C1--C2---C3 | ----------C4----C5
dev_1.2.3

AFTER MERGE:

		     			master
		     			  |

----C1----C2---C3------C4----C5 | dev_1.2.3

Excercise:

List all the branches

$ git branch

Create a new branch

$ git branch dev_1.2.3

Add some changes to newely created branch i.e dev_1.2.3

$ Modify/Add some files	
$ git add	
$ git commit

Now merge the code from dev_1.2.3 to master branch

Before merge, make sure that you are on target branch i.e master (source branch: dev_1.2.3) $ git checkout master

You have master code in source since currently checkout branch is master. Now bring/merge the changes from dev_1.2.3 to master by running below command.

Git merge command merges the changes from dev_1.2.3 to master. Verify the chages. $ git merge dev_1.2.3

Abservce the changes from dev_1.2.3 into master branch.

git push

MERGING W/ CONFLICT:

List all the branches

$ git branch

Create a new branch

$ git branch dev_1.2.3

Take a file which is common in master and dev_1.2.3 branch.

ex: Login.java

Make sure Login.java has below content in master and dev_1.2.3 branch

Login.java
	line#5 --> int a = 10;

To create a conflict situation, we need to modify same line in two branches with different content.

ex: Login.java (master)
		line#5 --> int a =100;
	
	Login.java (dev_1.2.3)
		line#5 --> int a = 200;

Now merge the code from dev_1.2.3 to master branch

Before merge, make sure that you are on target branch i.e master (source branch: dev_1.2.3) $ git checkout master

You have master code now, since currently checkout branch is master. Now bring/merge the changes from dev_1.2.3 to master by running below command.

Git merge command merges the changes from dev_1.2.3 to master.

$ git merge dev_1.2.3

Run git status command to list conflict file

Resolve the conflict and commit the merge

Run git push command to move the merge to Remote.

What is Conflict:

If two users modify the same file in source and target branches and if the same line has different content, git can't decide which user's code it has to take. we call this situation as conflict.

How do you resolve the conflict:

Open the conflict file--> remove conflict markers-->select the right content.
git add
git commit

git remote PULL FETCH PUSH CLONE

Store credentials: $ git config credential.helper store

NOTES: SVN & Git differences:

SVN is a centralised version control system. In svn, when a user checkout’s the repository, he will get only the source code. Repository is not distributed to the user. In SVN multiple users connect to a single/centralized server. If that server goes down, no user will be able to work.

Where as Git is distributed VCS. In the sense, when user clones the repository, he will get source code as well as complete repository on his local disk. since repository is distributed across multiple users and each user has their own local repository, user will be able to submit the changes locally without connecting to the master server. (i.e he can also work offline)

Git has staging area. Users can leverage this staging area to stage/save all the changes related to some issue/bug and commit everything at once into local repository. hence, all the changes will be recorded as part of single sha/commit. user's get an opportunity to logically group the changes and commit as single changeset. this enables better tracking.

Since git is distributed in nature, almost all transactions happen locally in the client machine and hence less overhead on the server so git is faster. Users are free to create any no. branches in Git. where as in svn, all branches reside in server side, so may cause svn to be overloaded with multiple requests.

Git seems to be good with merging.

Git stores each change as SHA values but SVN uses simple numbers as revisions.

Qns:

How do you pull a single branch / how do you make one branch as default. How to compare two branches.

explain: local to remote

creating local repository

git init nexamatic1

create remote reposiotry

making local repository as remote $ git remote add nexamatic1 https://github.com/nageshvkn/nexamatic1.git

git push nexamatic1

If local and remore repositories are same

$ git push --set-upstream nexamatic1 master

If local and remote repositories are different

git pull https://github.com/nageshvkn/nexamatic1.git

Note: when it opens a new window press: Ctrl+x

$ git push --set-upstream https://github.com/nageshvkn/nexamatic1.git master

abakashaGit/KotlinPractice

KotlinPractice

Git Commands : Day-1

What is VCS. Why we need VCS.

Day-2

Creating remote repository in github

Setting up mandatory configurations:

Day-3

Understand Git Jargon.

Skip staging

Creating up Local repository

Day-4

History - Deep Dive

Day-5

GIT Commands

Day-6

BRANCHING

List all the branches

Creating a new branch

Push new branch to remote repository

Switching from one branch to another

Creating and switching to a newly created branch

How do you clone a single branch from remote repository

List all remote branches

Day-7

Undoing the changes:

Show all the files with content difference that are modified as part of a commit

List only files that are committed as part of a revision.

Day-8

Merging:

FAST-FORWARD MERGE

BEFORE MERGE:

AFTER MERGE:

Excercise:

List all the branches

Create a new branch

Add some changes to newely created branch i.e dev_1.2.3

Now merge the code from dev_1.2.3 to master branch

You have master code in source since currently checkout branch is master. Now bring/merge the changes from dev_1.2.3 to master by running below command.

Abservce the changes from dev_1.2.3 into master branch.

git push

MERGING W/ CONFLICT:

List all the branches

Create a new branch

Take a file which is common in master and dev_1.2.3 branch.

Make sure Login.java has below content in master and dev_1.2.3 branch

To create a conflict situation, we need to modify same line in two branches with different content.

Now merge the code from dev_1.2.3 to master branch

You have master code now, since currently checkout branch is master. Now bring/merge the changes from dev_1.2.3 to master by running below command.

Run git status command to list conflict file

Run git push command to move the merge to Remote.

What is Conflict:

How do you resolve the conflict:

NOTES: SVN & Git differences:

Qns:

explain: local to remote

If local and remore repositories are same

If local and remote repositories are different