sed command in replace-background-path fails when running npm run dev

[sullyj3]

OS: linux
sed version: sed (GNU sed) 4.9

> cd build; sed -i "" "s#\$BACKGROUND_PATH#$(find app -wholename '*/immutable/background.*.js')#g" manifest.json; cd -

sed: can't read s#$BACKGROUND_PATH#app/immutable/background.b7e61a54.js#g: No such file or directory

The extension therefore fails to load:

Failed to load extension from: <path to project>. Could not load background script '$BACKGROUND_PATH'.

The extension successfully loads when I comment out the "service_worker" line of static/manifest.json

[sullyj3]

Oops, sorry, opened this on the wrong repo!