Re: shell and output redirection

From: Tanel Põder <tanel.poder.003_at_mail.ee>
Date: Fri, 2 Jul 2004 23:18:26 +0300
Message-ID: <042801c46071$bc06cdf0$e8879fd9@porgand>

> Programs are executed simultaneously. Pseudocode goes like this:
> create pipe
> fork process 1 {
> open pipe for output
> exec program 1 }
> fork process 2 {
> open pipe for input
> exec program 2 }

Ok, but if program 1 will issue a write request to the pipe now, shall it post process 2 and not continue before process 2 has completed?

As I saw from your trace, shell uses pipe() to create the pipe file descriptors for passing on data between processes. What if I create a pipe manually using mknod and run my two processes manually, does the data streaming work exactly the same way that with shell-generated pipe?

Tanel.

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Received on Fri Jul 02 2004 - 15:16:16 CDT