[TUHS] Shell control through external commands

[arnold at skeeve.com]

"Ron Natalie" <ron at ronnatalie.com> wrote:

> Traditionally, the shell recognized shell scripts and ran them in a new
> instance of the shell rather than calling exec on them.

I think that the way the shell "recognized" scripts was by having
exec fail, otherwise how would it know?  I think we'll have to go
grubbing in the source archives to be sure.

> It was a Berkeley hack to add a new exec magic number that happened to
> correspond to the characters #!.

ISTR reading on this list that #! was a post-V7 Bell Labs invention
that the BSD guys went and implemented themselves...

Can someone who was there please clarify?

Thanks,

Arnold