Useful Git Commands

1. Basic Setup

git config --global user.name "<Your Name>": Sets the user name for all repositories on your machine.
git config --global user.email "<Your Email>": Sets the user email for all repositories on your machine.

git status: Shows the status of the working directory and staging area (e.g., untracked files, changes staged for commit).
git add <file>: Stages a file to be committed.
- git add .: Stages all changes in the current directory.
git commit -m "Commit message": Saves staged changes to the repository with a descriptive message.

git log: Displays the commit history.
- git log --oneline: Shows a simplified, one-line history.
git diff: Shows the differences between various states.
- git diff HEAD: Compares the working directory with the last commit.

git branch: Lists all branches in the repository.
- git branch <branch-name>: Creates a new branch.
git checkout <branch-name>: Switches to another branch.
- git switch <branch-name>: An alternative, modern way to switch branches.
git merge <branch-name>: Merges changes from another branch into the current branch.

git remote add origin <repository-url>: Links the local repository to a remote repository.
git pull: Fetches changes from the remote repository and merges them into the current branch.
git push: Uploads local changes to the remote repository.

git reset: Undoes changes by resetting the HEAD.
- git reset --soft <commit>: Moves HEAD but keeps changes staged.
- git reset --hard <commit>: Moves HEAD and discards all changes.
git checkout -- <file>: Discards changes in the working directory for a specific file.
git revert <commit>: Creates a new commit that reverses a specific commit.

git tag <tag-name>: Creates a lightweight tag for a commit.
git tag -a <tag-name> -m "Tag message": Creates an annotated tag with a message.

git fetch: Downloads changes from the remote repository but doesn’t merge them.
git pull origin <branch>: Fetches and merges changes from a specific branch on the remote.
git push origin <branch>: Pushes changes from the current branch to the remote.

git show <commit>: Shows details about a specific commit.
git blame <file>: Shows who made the last change to each line of a file.
git log --graph --all --decorate: Displays a graphical view of the commit history.

git cherry-pick <commit>: Applies the changes from a specific commit onto the current branch.
git rebase <branch>: Reapplies commits on top of another base branch.

“Merge or rebase?” - rebase for your own local feature branch to keep history linear before merging; merge for shared branches. Never rebase a branch others have pulled, because rewriting shared history forces everyone to recover manually.
“How do you undo a commit that’s already pushed?” - git revert, which adds a new commit undoing the change and preserves shared history. reset --hard rewrites history and is only safe on branches nobody else has.
“How do you recover something you think you destroyed?” - git reflog. It records where HEAD has been, so a botched reset or a deleted branch is usually recoverable for a couple of weeks.