Run external script

thumbnails/Tupfile

@@ -1,7 +1 @@
-: asset.raw |> !tup_preserve |>
-: asset.raw |> cp %f %o |> asset.thumbnail
-
-# tup error: Unable to create output file 'asset.thumbnail' because it is
-# already owned by command 16.
-#: foreach *.raw |> !tup_preserve |>
-#: foreach *.raw |> cp %f %o |> asset.thumbnail
+run ./generate_thumbnails.tup

thumbnails/generate_thumbnails.tup

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+for i in *.raw; do
+    echo ": $i |> !tup_preserve |>"
+    echo ": $i |> cp %f %o |> %B.thumbnail"
+done