in reply to open (to read) and kill a pipe to a pipe

I'm not even sure what signal I should be sending with the kill

Windows has two signals, Ctrl-C and Ctrl-Break. It uses message passing primarily, but that's for application with Windows. It can terminate processes forcibly.

I think you can send the Ctrl-C and Ctrl-Break signals using kill, but I don't know which numbers do this.

kill 9 surely results in the the system call to terminate a process. That's drastic.

BUT it does not kill the gzip or mycommand processes when it gets to the "kill 9, $pid".

It kills the shell whose pid is in $pid. This doesn't kill the shell's children. I don't know one would achieve that.

One solution would be to eliminate the shell and do the piping yourself.

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Re^2: open (to read) and kill a pipe to a pipe
by darist (Initiate) on Aug 26, 2010 at 21:59 UTC
    Thanks! This looks promesing... but I can't figure it out.

    I tried open2 (since I don't need the stderr from open3), but I don't even get the output of mycommand to show up...
    what should I put in the while(< ??? >)... or did I even use the open2 command properly? 
    use IPC::Open2;

$file = $ARGV[0];

local *FRGZ;
local *TOGZ;
local *FRCMD;

$pid1 = open2(*FRGZ, *TOGZ, "gzip -dc $file");
$pid2 = open2(*FRCMD, '<FRGZ', 'mycommand');

while (<*FRCMD>)
{

    print;
}

    [download]
    maybe someone can provide an example of how to make this work...
    My idea here is for the command "gzip -dc $file" to pipe its output to *FRGZ. Then I would pipe *FRGZ into "mycommand" and the output would be on *FRCMD .... ???
[reply]
[d/l]

      open2 mixes STDERR into STDOUT, its arguments are "backwards", and it just ends up calling open3 anyway. I avoid it. 

      use strict;
use warnings;

use IPC::Open3 qw( open3 );

my $file = $ARGV[0];
open(local *TO_CHAIN, '<', $file)
   or die("Can't open \"$file\": $!\n");

my $gz_pid = open3('<TO_CHAIN, local *PIPE, '>STDERR', 'gzip -dc');
my $mc_pid = open3('<PIPE', local *FR_CHAIN, '>STDERR', 'mycommand');

while (<FR_CHAIN>) {
   print;
}

      [download]
[reply]
[d/l]

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