On Thu, 14 Jul 2005, Dave Anderson wrote:
> >I did not check your script, but POSIX says this:
> >
> >$ Expands to the decimal process ID of the invoked shell. In a
> > subshell (see Shell Execution Environment ), '$' shall expand to the
> > same value as that of the current shell.
> >
> >There's a similar phrase in the man page,
>
> Sorry if I was unclear -- it's certainly documented (though exactly
> what "original" as used in the man page means wasn't totally obvious to
> me without doing some testing); my curiosity is about the reasoning
> behind making the PID/PPID of the "original" shell easily available
> while leaving those of the subshell inaccessible.
The developer of the shell has the freedom to either spawn a separate
process for a subshell expression or execute the subshell commands in
the in a newly created enviroment that is a copy of the current
environment environment.
It is wrong to assume using (...) will actually create a new process.
-Otto
