Git Learning

• Git is the most popular version control system in the world.

Version control system

• A version control system recoeds the changes made to our code over time in a special database called repository .

Repository

• Repository means a place or something to store data ( Git usualy stores the code data )

Advantages

• We can see the project history that who changes them and when.

• We can also relative the previous data.

Categories

• Centralized.

• Distributed.

Centralized

• In centralized systems, all team members must connect to the server to get the latest copy of the code.

• Need to share the code with others.

• EXAMPLE: subversion and team Foundation Server.

Disadvantages

• If server goes offline , no one can access.

Distributed system

• we will have copy of project code , history in local system.So even the file gos offline , we can synchronise the code between us.

• EXAMPLE : Git and Mecurial.

Git

• It is free source.
• Open source,
• Super fast.
• Scalable.
• CheapBranching/ Merging.

Using Git ( Git environment to use )

• Command line --> It is always available and fast.
• Code Editors , IDE --> Ex: VS code.
• Grafical User Interface (GUI tools).
• Source Tree.

Installing git ( Terminal )

• mac OS --> Press command + space and type terminal.
• Windows OS --> Click the search icon and type cmd.
• Ubuntu OS --> click Contril + ALT + t.

Git commands

git --version --> To see the version of git.

NOTE : To install or update git version visit : git-scm.com

Configuration settings in git

• We should specify the following data while configuring git.
  • Name .
  • E-mail.
  • Default editor.
  • Line Ending.

Levels of configuration setting

• System Level --> For all users.
• Global Level --> All repositories of the current user.
• Local Level --> The current repository.

git configuration commands

• git config --global user.name "User name " --> To set user name.
• git config --global user.email "email" --> To set email id .
• git config --global code.editor "code --wait" --> To set default editor.
• git confug --global -e --> To edit above details.
• git config --global core.autocrlf input --> Use this command for linux / mac.
• git config --global core.autocrlf true --> Use this command for windows.

Importance of end line

• Windows uses end of lines as /c or /n as next lines.

• Ubunu uses only /n as next line.

git help

• git config --help --> to get help from git .
• git config -h --> Shortcut to get help.

Basic git workflow

• Step 1 : Create directory.
• step 2 : Initialize git (empty) by git init command . A sub file is ceated within the fle . We cannot see that , we can only see using ls -a command. .git file will be present in the same file which contains copy of the current project files. NOTE : rm -rf .git --> to remove sub git repository (DON'T do this)
• Step 3 : Finish work .
• Step 4 : After completion , we nedd to stage our changes using git add . command. Staging area is an intermediate state allows us to review our work before record it using commit the changes . We can also unstage them and add to another commit .
• Step 5 : After staging , Use git command -m "meaningful message" commanded to commit the changes. commit is like taking snapshots of our work that means recording the work and maintain history.

Important things to know about basic flow og git

• Must use valid commit message to maintain good history of work . It is used to get easy identification of particular portion of the code.

• Our staging area will remain the last version of our code with last commit. It will not delete the old version once it committed.

• Each commit consists Unique id, message ,Date/time ,Author and complete snapshot of our code.

• The unique id is generated by git unique for each commit.

• The snapshot takes complete project everytime , not updating the old.

• Each commit compresses the content and it doesn't store duplicate content.So , no data storage is wasted.

Staging files

• git status --> It is used to see the status ofthe working directory on the staging area.

Methos of staging

• git add --> for single file.
• git add --> for multiple files.
• git add . --> for all file ( Be careful while using ) .
• git add *.txt --> files that contains .txt extensions.

Commiting changes

• git commit -m "message" --> messages should be meaningful.
• To give a detailed commmit message for good understanding. Use / Type --> git commit and press enter Type your short and detailed descreption in the opened file and close yhe file to stop the process.

Best practice of commiting

• As you reach a state you want to record Then , make a commit.
• Each commit should represent a logically seperate change set.
• Always use past tence in commit message.

Skipping the staging area

• Mostly DO NOT use this method.
• If we are sure on our code (Whenever our code is not require review , skip yhe staging area )
• Use git commit -am "without staging" Here a is fr all and m is for message.

Removing files

• Commands to remove files from our local and the repository as well are below:

• git rm -r filename.

• git rm -r -f filname --> to force remove the file.

• git rm -r --cached filename --> not to remove.

Renaming our moving files

• i mv filename1 filename2 --> here moving and rename happens simultaneously.

Ignoring files

• Special file --> .giignore --> attach this file in te file where we don't need stageing.

Short status

• git status -s --> this will show the short type of work status .

Viewing staged and unstageed files

• git diff --staged --> This will display a detailed comparison of old and current versions of last commited files to git.

DIFF Tools

• There are lot of differnet tools first configure the setting to make vs code as default DIFF TOOL.

• git config --global diff.tool vscode

• git config --global difftool.vscode amd "cde --wait"

Viewing the history

• git log --> It will show the history of all commits made with the unique id, author, date and time.
• git log --oneline --> It will display the shortest things in history.
• git log --oneline --reverse --> It will show the history in reverse order.

Viewing the commit

• git show HEAD -->It is also display the last commit details with detailed descreption.
• git ls-tree HEAD~1

Git objects

• commits.
• BLobs(Files).
• Trees (Directions).
• Tags.

Unstaging files

• git restore --staged filename

Discarding local changes

• git restore .
• git clean -f

Restoring a file to an earlier version

• git restore --source=HEAD~1 filename