I also can’t get that to work and I don’t get any error messages in the logs.
A little bit of searching suggests that the exec binding doesn’t work well (or possibly at all) with either redirects or pipes.
See -
https://community.openhab.org/t/rule-issue/106732/9
https://community.openhab.org/t/send-the-value-from-a-slider-to-a-script-py/103782/29
https://community.openhab.org/t/concatenate-inside-exec-command/105983/21
I’d suggest getting a short script to work that doesn’t use a redirect or pipe as a starting point.