github上fork repo的问题

Question

github上fork了一个repo，这个repo是复制了一份到我的账号里
如果原始项目的某个分支update了，我fork过来的repo会自动更新吗？

很多同学没理解我意思，是这样，fork一个project之后
git remote add upstream git_url
此时git branch -a假设输出：
master
origin/master
origin/dev
upstream/master
upstream/dev

如果运行git fetch upstream则upstream的各个分支被更新了，但我fork的分支
origin/master
origin/dev
却并没有更新，是不是更新所有origin分支都需要merge之后手动push？
如果project的branch很多，岂不非常麻烦？

Answer 1

If the original repo you forked your project from gets updated, you can add those updates to your fork by running the following code:

git fetch upstream
# Fetches any new changes from the original repo

git merge upstream/master
# Merges any changes fetched into your working files

Answer 2

First, specify the original warehouse as upstream:

git remote add upstream https://github.com/被fork的仓库.git

Execute the command mentioned above again:

git fetch upstream
    git merge upstream/master