Whats the difference between `git checkout -b branch` and `git checkout -b branch origin/branch`

Question

As we know, I create a local branch branch I can use:

git checkout -b branch 

But there is a git checkout -b branch origin/branch

I do't know whats the difference between them, who can tell me about it? Does this command will create a remote origin/branch ?

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EDIT

I have three questions:

1.Whether the git checkout -b branch origin/branch create a branch in local repo?

2.Does git checkout -b branch origin/branch create a origin branch for remote repo?

3.Or is the git checkout -b branch origin/branch is create a branch from local repo master branch, and git checkout -b branch create a branch from current branch?

Answer 1

1.Whether the git checkout -b branch origin/branch create a branch in local repo?

Yes.

2.Does git checkout -b branch origin/branch create a origin branch for remote repo?

No, it creates a local branch which is identical to origin/branch (status of last pull)

3.Or is the git checkout -b branch origin/branch is create a branch from local repo master branch, and git checkout -b branch create a branch from current branch?

The difference is the "what will be in the new branch". origin/branch refers to a local reference (can't be modified!) of the remote repo, branch is a local branch.

Have a look at the very good explanations in the git book

Answer 2

As per the manual :

git checkout -b|-B <new_branch> [<start point>]

Specifying -b causes a new branch to be created as if git-branch were called and then checked out. […]

So calling git checkout -b new_branch or git checkout -b new_branch start_point is equivalent to the following:

git branch new_branch
git checkout new_branch

# or

git branch new_branch <start_point>
git checkout foo

So let's check git-branch on what happens with that start point:

The command's second form creates a new branch head named <branchname> which points to the current HEAD , or <start-point> if given.

Not specifying a start point means that the start point is HEAD , so git branch new_branch is equivalent to git branch new_branch HEAD .

So what does git branch new_branch start_point do? Create a new branch new_branch that points at the commit specified by start_point . If you don't specify one, then that will be HEAD which is the currently checked out commit.

To sum this up: git checkout -b branch will create and check out a new branch branch that is at the exact same location you currently are at. git checkout -b branch origin/branch will create and check out a new branch branch that points at origin/branch which is the local copy of the remote branch branch on the origin remote.