git 更新远程仓库至folk仓库

如下情形：在github上fork的一个仓库remote-rep到自己的仓库下remote-rep1，clone remote-rep1到本地目录下进行修改，修改后push到remote-rep1。若原始仓库remote-rep更新了，想要把这些更新也更新到自己的仓库中remote-rep1。可进行如下操作：

# 添加远程仓库，可称为 upstream
git remote add upstream https://github.com/[source]/remote_rep.git

# 获取远程仓库的更新
#Fetch all the branches of that remote into remote-tracking branches,
# such as upstream/master:
git fetch upstream

# Make sure that you're on your master branch:
git checkout master

# Rewrite your master branch so that any commits of yours that
# aren't already in upstream/master are replayed on top of that
# other branch:
git rebase upstream/master

更新完后，再将本地仓库的修改后推送至remote-rep1：

#only need to use the -f the first time after you've rebased
git push -f origin master

参考资料
https://stackoverflow.com/questions/7244321/how-do-i-update-a-github-forked-repository