title: Use a modified variable in bash script, trying to change git branch programatically
body: <p>I'm playing around with my custom commands, and I'm currently trying to change a remote Git branch programatically using bash.</p>
  
  <pre><code>issue() {
      if [ `git branch --list issue_$1` ]
      then
          git checkout issue_$1
      else
          git checkout -b issue_$1
          git branch -u origin issue_${1}
      fi
  }
  </code></pre>
  
  <p>The idea is this function will try to find the branch issue_X, if it does it switches, otherwise it creates and sets the remote origin.</p>
  
  <p>The problem is <code>git branch -u origin issue_${1}</code> I don't know how to do this, and I'm having trouble googling for it because I don't know what this process is called.</p>
  
  <p>Thanks a lot for the help!</p>