However I am still seeing a LONG period of hanging for some hosts that is happening AFTER the timeout is reached, and when the subroutine is trying to CLOSE the pipe.

Why is this? By code is below

That's because perl is being too polite to the traceroute process whilst closing the pipe: it just sends SIGPIPE (see close) - which traceroute ignores - then waits till the other process closes the pipe, just in case you were interested in it's output.

The piped open to a command returns that's processes PID.

You could use that to be unpolite and then close the pipe: 

    if( my $pid = open my $pipe, "traceroute -I -n $hostname |" ) {
        while(1) {
            last if ...
        }
        kill 2, $pid;
        close $pipe;
    }

[download]

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In reply to Re: Timing out a traceroute by shmem
in thread Timing out a traceroute by vancetech

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