Hi @wburgess!
Thanks for reaching out, this is a great question.
The QIIME framework doesn't currently support direct result piping. However, one of our community contributors has built a plugin that does allow for pulling values directly from an output file, which may help you with this workflow. Details on this plugin, along with installation instructions can be found here.
As another alternative, you could achieve this with a small script that contains all of your QIIME commands (above) along with the desired value from your output file that you'd extract using Python (or another language of your choice). Here is an example of how you could do this in Python. That being said, this may be a heavier lift since you are not familiar with Python.
Hopefully this helps provide you with a couple of options for automation in this workflow - please let us know if you have any additional questions moving forward!
Cheers,
Liz