while / until feature request

And if there's a better way around it other than a feature request,
I'm very willing to do so:

Having a while / until option for the command and shell tasks.

Some times you want to keep running a command until it returns true,
or contains some sort of output. Let's say you wanted to keep
checking /tmp until a file showed up:

something like:

command: ls -1 /tmp|grep myfile
until: true
interval: 5
retries: 100

Yep...

We already have a ticket on this one, making a note to merge your
comments into that one so we have them all in one place...