Hello monks, trying to run a system command using a file handle and insert its output to a txt box. Ive tried fileevent and fork. Both failed miserably.

my $mw = MainWindow->new;
my $b1 = $mw->Button(-text => 'Go', -command => sub{&go})->pack();
my $b2 = $mw->Button(-text => 'Exit', -command => sub{exit} )->pack();

my $text = $mw->Scrolled('Text',-scrollbars=>'e')->pack;

MainLoop;

sub go {
    
    my $pid = fork();
    if($pid == 0) {
    open(H, "nmap -A localhost |");
    while(<H>) { $text->insert('end',$_); }
    }
}
[download]

Thanks, -rjb

#!/usr/bin/perl

use strict;
use warnings;
use Tk;
use Tk::IO;
use Tk::ROText;

my $entry_var='';
my $pid;
my $mw = MainWindow->new(-title => 'Tk::IO');
$mw->geometry('570x500');
my $top_frame = $mw->Frame(
    -relief => 'groove', 
    )->pack(-side=> 'top', -fill => 'x');
my $top_frame_left = $top_frame->Frame(
    -relief => 'groove',
    )->pack(-side => 'left',-fill => 'x');
my $top_frame_right = $top_frame->Frame(
    -relief => 'groove',
    )->pack(-side => 'right', -fill=>'x');

my $bot_frame = $mw->Frame(
    -relief => 'groove', 
    -borderwidth => 5
    )->pack(-side=> 'bottom', -expand => 1,-fill => 'both');
my $clear_button = $top_frame_left->Button(
    -text => 'Clear',
    -command => sub { &clear_text }
    )->pack(-side => 'left');
my $start_button = $top_frame_left->Button(
    -text => 'Start',
    -command => sub { &go }
    )->pack(-side => 'left');
my $stop_button = $top_frame_left->Button(
    -text => 'Stop',
    -state => 'disabled',
    -command => sub { &stop }
    )->pack(-side => 'left');
my $label = $top_frame_left->Label(
    -text => 'Enter Host'
    )->pack(-side => 'left');
my $entry = $top_frame_left->Entry(
    -textvariable => \$entry_var
    )->pack(-side => 'left');
my $exit_button = $top_frame_right->Button(
    -text => 'Exit',
    -command => sub { exit }
    )->pack(-side => 'right');
my $text_box = $bot_frame->Scrolled(
    'ROText',
    -wrap => 'word',
    -font => 'rk24',
    -background => 'black',
    -foreground => 'green',
    -scrollbars => 'se'
    )->pack(-expand => 1, -fill => 'both');

MainLoop;

sub go {
    if($entry_var eq ''){
        $text_box->insert('end',"No host specified\n");
        return;
    }
    $start_button->configure(-state => 'disabled');
    $stop_button->configure(-state => 'active');
    
    my $usr_command = Tk::IO->new(
        -linecommand => sub 
            { $text_box->insert('end', shift()) },
        -childcommand => sub {
            $text_box->yview('end');
            $start_button->configure(-state => 'active');
            $stop_button->configure(-state => 'disabled')});
        $pid = $usr_command
        ->exec("nmap $entry_var 2>&1") or die $!;
}

sub stop {
    kill INT =>  $pid if kill 0 => $pid;
    $start_button->configure(-state=>'active');
    $stop_button->configure(-state=>'disabled');
    $text_box->insert('end', "Cancelled...\n");
    $text_box->yview('end');
}

sub clear_text {
    $text_box->delete('0.0','end');
}
[download]