On 6/18/10 10:05 AM, Dr. Werner Fink wrote:
> as now is visible the last command in the pipe sequence done
> in the bash is a real sub process whereas in the ksh it is not.
>
> The question rises: Why does the bash require a sub peocess/shell
> for the final command of a pipe sequence.
It's an implementation decision: the code as it exists today is more
straightforward. Since Posix requires that all commands in a pipeline
be executed in a subshell environment, though it allows the ksh behavior
as an extension, there's been no requirement to change it.
If anyone would like to take a shot at changing the code to not fork when
executing a command with a pipe for stdin, I'd be glad to take a look at
the result.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
