什么是`git push origin master`？帮助git的refs，head和remotes

Question

I have a question about what git push origin master does:

• I know that origin is the remote (aka GitHub)
• git push origin master is the same as git push origin master_on_my_machine:master_on_github

I don't know if:

• master_on_my_machine is equal to /refs/heads/master
• master_of_github is equal to /refs/remotes/origin/master

If it's equal, should it be possible to do git push origin refs/heads/master:refs/heads/origin/master ?

Finally, what I want to do is only type git push and git pull when:

• I'm on a master branch
• I want to push and pull from a my_test branch on github, only typing git push and git pull .

Answer 1

Git has two types of branches: local and remote . To use git pull and git push as you'd like, you have to tell your local branch ( my_test ) which remote branch it's tracking. In typical Git fashion this can be done in both the config file and with commands.

Commands

Make sure you're on your master branch with

1) git checkout master

then create the new branch with

2) git branch --track my_test origin/my_test

and check it out with

3) git checkout my_test .

You can then push and pull without specifying which local and remote.

However if you've already created the branch then you can use the -u switch to tell git's push and pull you'd like to use the specified local and remote branches from now on, like so:

git pull -u my_test origin/my_test
git push -u my_test origin/my_test

Config

The commands to setup remote branch tracking are fairly straight forward but I'm listing the config way as well as I find it easier if I'm setting up a bunch of tracking branches. Using your favourite editor open up your project's .git/config and add the following to the bottom.

[remote "origin"]
    url = git@github.com:username/repo.git
    fetch = +refs/heads/*:refs/remotes/origin/*
[branch "my_test"]
    remote = origin
    merge = refs/heads/my_test

This specifies a remote called origin , in this case a GitHub style one, and then tells the branch my_test to use it as it's remote.

You can find something very similar to this in the config after running the commands above.

Some useful resources:

• http://www.kernel.org/pub/software/scm/git/docs/git-branch.html
• http://gitready.com/beginner/2009/03/09/remote-tracking-branches.html

Answer 2

Or as a single command:

git push -u origin master:my_test

Pushes the commits from your local master branch to a (possibly new) remote branch my_test and sets up master to track origin/my_test .