A trick with perl

[Andrew Pimlott]

On Sat, Jan 03, 2004 at 04:51:09PM -0800, Chris Fortune wrote:
>         # Loop for each email
>             open NP, ">$RAM_file.FIFO" or die $!;
>             print NP "$head\n$body\n^D"; # ^D is EOF, just in case
>             close NP;

You're heading for headaches because a pipe can only buffer so much
input, so your program will hand when you have a long message.
Using Open2 has the same problem.  The simplest solution is to use a
temporary file at one end:

    open FILTER, "| prog > result";
    print FILTER "$head\n\n$body";
    close FILTER;
    open RESULT, "<result";

Also, that ^D is bogus.  ^D only means end of file when pressed in a
terminal; it does not appear in the file stream and can only confuse
the filter.

Andrew