Use:

git commit -a

-a on the command line instructs git to commit the new content of all tracked files that have been modified. You can use

git add <file>

or

git add -A

before git commit -a if new files need to be committed for the first time.

The main point in Git vs SVN debate boils down to this: Git is a distributed version control system (DVCS), whereas SVN is a centralized version control system.

Git is a Distributed Version Control system (DVCS). It can track changes to a file and allows you to revert back to any particular change.

Its distributed architecture provides many advantages over other Version Control Systems (VCS) like SVN one major advantage is that it does not rely on a central server to store all the versions of a project’s files.

In the simplest terms, git pull does a git fetch followed by a git merge.

• When you use pull, Git tries to automatically do your work for you. It is context sensitive, so Git will merge any pulled commits into the branch you are currently working in. pull automatically merges the commits without letting you review them first. If you don’t closely manage your branches, you may run into frequent conflicts.

• When you fetch, Git gathers any commits from the target branch that do not exist in your current branch and stores them in your local repository. However, it does not merge them with your current branch. This is particularly useful if you need to keep your repository up to date, but are working on something that might break if you update your files. To integrate the commits into your master branch, you use merge.

• A branch is just a separate version of the code.

• A pull request is when someone take the repository, makes their own branch, does some changes, then tries to merge that branch in (put their changes in the other person's code repository).

• A fork is a remote, server-side copy of a repository, distinct from the original. A fork isn't a Git concept really, it's more a political/social idea.
• A clone is not a fork; a clone is a local copy of some remote repository. When you clone, you are actually copying the entire source repository, including all the history and branches.
• A branch is a mechanism to handle the changes within a single repository in order to eventually merge them with the rest of code. A branch is something that is within a repository. Conceptually, it represents a thread of development.

The Centralized Workflow uses a central repository to serve as the single point-of-entry for all changes to the project. The default development branch is called master and all changes are committed into this branch.

Developers start by cloning the central repository. In their own local copies of the project, they edit files and commit changes. These new commits are stored locally.

To publish changes to the official project, developers push their local master branch to the central repository. Before the developer can publish their feature, they need to fetch the updated central commits and rebase their changes on top of them.

Compared to other workflows, the Centralized Workflow has no defined pull request or forking patterns.

You accidentally committed wrong files to Git, but haven't pushed the commit to the server yet. How can you undo those commits from the local repository?

It’s a two steps process. First you fetch the changes from a remote named origin:

git fetch origin

Then you merge a branch master to local:

git merge origin/master

Or simply:

git pull origin master

If origin is a default remote and ‘master’ is default branch, you can drop it eg. git pull.