git push -u是什么意思？

我有两个不同版本的git。在1.6.2版本中，git push没有该-u选项。它仅出现在1.7.x版本中。

在文档中，-u与变量相关

branch.<name>.merge

在中git config。此变量描述如下：

Defines, together with branch.<name>.remote, the upstream branch 
for the given branch. It tells git fetch/git pull which branch to merge.

什么是上游分支？

“上游”是指其他人将从中获取的主要存储库，例如您的GitHub存储库。-u选项自动为您设置该上游，从而将您的存储库链接到中央存储库。这样，将来Git会“知道”您要推送到的位置以及您要从哪里提取的信息，因此您可以使用git pull或git push不使用参数。稍有下降，本文解释并演示了此概念。

这不再是最新的！

Push.default is unset; its implicit value has changed in
Git 2.0 from 'matching' to 'simple'. To squelch this message
and maintain the traditional behavior, use:

  git config --global push.default matching

To squelch this message and adopt the new behavior now, use:

  git config --global push.default simple

When push.default is set to 'matching', git will push local branches
to the remote branches that already exist with the same name.

Since Git 2.0, Git defaults to the more conservative 'simple'
behavior, which only pushes the current branch to the corresponding
remote branch that 'git pull' uses to update the current branch.