(rule (with-stdout-to bar (echo "from bar")))

(alias
 (name default)
 (action
  (progn
   (echo "Initial value of %{env:DUNE_FOO=unset}\n")
   (setenv DUNE_FOO XXXX (echo "Now set: %{env:DUNE_FOO=unset}\n"))
   (setenv DUNE_FOO %{read:bar} (echo "From bar: %{env:DUNE_FOO=unset}\n")))))
