PHP - 将表单输入作为变量传递给bash脚本?

I'm working on a quick and dirty webapp that is designed to wrap common tasks I accomplish with shell scripts into a web interface for a couple of users that cannot use the CLI.

My only issue is passing a value entered into a form to be used as an argument against said shell script. For example, one bash script simply takes an email address as an argument. What is the best way to pass this along to my bash script to be executed?

I was thinking of using system() as the PHP show that it could work in this case and then print out the result that the script displays on the webpage but I'm having issues figuring out where to even start.

My form code is mostly placeholder right now and is as follows:

  <input type="text" id="syncAcct" runat="server" name="syncAcct" class="form-control" placeholder="user@domain.tld">
  <span class="input-group-btn">
    <button class="btn btn-default" runat="server" name="submit" type="button">Sync Quota</button>

I need to take the input from that form (an email address) and pass it to my script (e.g. syncQuota.sh user@domain.tld), if I can somehow print the result from that on the page as well that would be a nice bonus but I'm really working towards basic functionality and am quite lost at this point.

Any help you could provide would be greatly appreciated.