Notes - > Git Basics , git commands

[These are my git notes related to git commands]
Ref: Git Tutorials - by Corey Schafer.

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** Fundamentals

Git is a Distributed version control. ...Git has a local and remote repositories.

 git  --version 
 git help <verb>  OR  git <verb> --help

Set Configs values :

 git config --global user.name "Jon Doe"
 git config --global user.email "jondoe@example.com"
 git config --list   // all values will be listed

Scenario 1 : Existing Project Local 

 cd  /project_dir
 git init     //Initializes a git repo .. creates a .git/ dir
 git status    // check status
 touch .gitignore    // .txt file to add files dirs to be ignored by git.
 git add -A  // add all files to staging area.
 eg. git add .gitignore   // add .gitignore to the repo
 git commit -m "<message>"  // make changes to the local repo
 git reset  // remove files from staging
 git log   // log 

Scenario 2 : Remote Project Repo 
 git clone <url> <location_to_clone>   //clone remote repo to local system
 git remote -v  //  view info about the remote repo
 git branch -a  // list all branches in the repo
      <after making changes to the code, commit the changes locally before pushing>
 git diff // shows changes 
 git status  // shows the modified files
 git add -A  // add all files to staging 
 git status  // shows files are ready to be committed
 git commit -m "<message>"   // commit changes locally
 git pull origin master   // pull latest code (in case there are more people working on the repo)
 git push origin master   // push changes to master branch on remote.

Instead of working on the master branch, its recommended to create a branch of the feature to work on. 
 git branch -a  // list branches
 git branch <branch_name>  // Create new branch
 git checkout <branch_name>  // switch to <branch_name>
 <make changes to the code>
 git commit -m "<message>"  // commit changes to <branch_name>
 git push -u origin <branch_name>  // push changes to <branch_name> on remote repo
 

 Now we need to Merge the changes in the custom branch to the master & then delete the custom branch.

 git checkout master   // switch to master branch
 git  pull origin master  // pull the latest code
 git branch  --merged   // lists the branches that have been merged so far
 git merge <branch_name>  // Merge changes from <branch_name> to master.
 git push origin master  // push the merged changes to master.
 git branch --merged // check if the changes from <branch_name> have been merged.
 git branch -d <branch_name> // Deletes branch locally
 git push origin --delete <branch_name>  // delete branch from remote repo.

 

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** Undoing Bad commits 

git status 
git diff  //see the code changes made

A. In case we want to change the commit message 

 git commit -m "Wrong message"   // user enter a wrong commit message
 git log   // check the message in logs
 git commit --amend -m "Correct message"  // Amends the commit message
 git log   // double-check in logs

B. In case of a committed file (Accidentally made changes to wrong branch)
   Eg.  Changes committed to master instead of feature branch
 git log --stat // git files changed within the commit
 git checkout master // switch to master.
 git log // copy 5-6 chars of the commit hash
 git checkout feature // switch to feature branch
 git cherry-pick <copied commit hash>  // copied above commit hash
 git log  // commit from master is now in feature branch 
 git checkout master // go back to master branch
 git reset

Git Reset:

1. Git Reset Soft:

 git reset --soft <commit hash_str>

In this case the 'git log' will no longer have the commit but in the 'git status' the changes will be as it is in the staging. So we wont lose any work.

2.   Git Reset (Default/Mixed) :

     git reset <commit hash_str>

In this case the 'git log' will no longer have the commit just as  git --soft, but in this case the changes will move out of the staging area to the working area.

3. Git Reset  Hard:

git reset --hard <commit hash_Str> 

In this case  modifications will be completely reverted. Except for the un-tracked files. 

 

4. To get rid of untracked files and directories :

 git clean -df   // -d for dirs; f for force

 ** In case you run '' git reset --hard"  by mistake:

            git reflog  // shows commits in the order of when we last referenced them.

 git checkout <commit hash_str> // Checkout to the commit hash obtained from above reflog.

             git branch backup  //create a backup of the previous rollback.                

Git Garbage collector run once in 30 days and above retrieval will  work prior to the garbage collector running. 

Git Revert:  Git revert un-does the changes and adds additional commits of the changes.

 git revert <commit hash_str>

 

Git Stash :  [pending ]