shebang

In scripting, a shebang line will tell its interpretor.

In most cases, use env, so users may install the interpretor anywhere.

#!/usr/bin/env lang

But occasionally, do not use env, as it may not be present in some systems:

#!/bin/sh

(Well, even busybox has env. But Android by default does not have env. Though #!/bin/sh won't work, either, since Android uses #!/system/bin/sh)