There's no such thing as /bin/env, though I let that slip by because my
distro redirects /bin to /usr/bin.
I believe "#! /bin/sh" is even more standard that "#! /usr/bin/env sh",
and that's what I used everywhere anyway.
-#! /usr/bin/env sh
+#! /bin/sh
# This file is dual-licensed. Choose whichever licence you want from
# the two licences listed below.
-#! /bin/env python3
+#! /usr/bin/env python3
# This file is dual-licensed. Choose whichever licence you want from
# the two licences listed below.