用git init（默认创建的是私人的仓库）创建的仓库，推送是不会成功的。
因此在git server端，我们要用 git --bare init --shared=group 来创建一个bare库，意思是创建一个共享的多人合作的仓库，这样则可以往新建的远程仓库中推送更新。
在git client 端，可以用如下命令对远程仓库进行跟踪：
git clone ssh://192.168.100.103/~/jj/.git
在有改动的情况下，可以使用：
git push origin master， 将本地master分支push到远端的master分支
注意，远程仓库必须是bare库，若为非bare库，则不能提交，会提示：
refusing to update checked out branch: refs/heads/master
remote: error: By default, updating the current branch in a non-bare repository
remote: error: is denied, because it will make the index and work tree inconsistent
remote: error: with what you pushed, and will require 'git reset --hard' to match
remote: error: the work tree to HEAD.
remote: error:
remote: error: You can set 'receive.denyCurrentBranch' configuration variable to
remote: error: 'ignore' or 'warn' in the remote repository to allow pushing into
remote: error: its current branch; however, this is not recommended unless you
remote: error: arranged to update its work tree to match what you pushed in some
remote: error: other way.
remote: error:
remote: error: To squelch this message and still keep the default behaviour, set
remote: error: 'receive.denyCurrentBranch' configuration variable to 'refuse'.