can't set upstream of git branch code example

Example 1: git set upstream

git branch --set-upstream-to <remote-branch>

// example
git branch --set-upstream-to origin feature-branch

// show up which remote branch a local branch is tracking
git branch -vv

// short version to set upstream with very first push
git push -u origin local-branch

Example 2: git configure upstream for branch push and pull

# if remote_branch_name == local_branch_name
$ git push -u origin HEAD