>>      2) At the time of this test campaign, the shebang line of vdev
>> scripts was #!/bin/dash, which doesn't work in Busybox. It should be
>> replaced by #!/bin/sh which works in all cases.
> This isn't necessarily true. Both dash and the usual busybox sh are
> forks of the Amquist shell (ash) which is supposed to be enable to
> execute scripts written in the Bourne shell language/ for the
> standardized /bin/sh but they also provide extensions of their own (eg,
> like bash, dash supports lexically scoped function variables but the
> Bourne/ standard shell doesn't). The busybox ash can also compiled w/o
> certain features, eg, arithmetic expansion.

     There's no theory behind that. It's just practical and the result 
of experimenting.

     The way Busybox works is all applications are links to 
/bin/busybox. When invoqued, /bin/busybox calls a dispatcher function 
which determines which applet to call (there is one applet per supported 
application) from the name of the link. And there is no applet named 
'dash' in Busybox. But Busybox knows 'ash' and 'sh', which point to the 
same applet.

     On the other hand, the default shell in Debian, the one invoked by 
/bin/sh, is dash. I guess in every distro /bin/sh points to the 
~POSIX-compliant shell. Therefore '#!/bin/sh' should just work everywhere.

     Didier