Your ftp transaction is blocking the Tk EventLoop. The terms you want to look for are "blocking and non-blocking". This is the same sort of problem you can experience in a plain Perl script, when you use "system" to run something, instead of doing a "fork-and-exec". In the system case, your program will run the called command ( in your case ftp ), and the rest of the script will wait for ftp to finish. If you "fork-and-exec", the ftp is spawned off as a new independent process, so your original program can continue to run. The problem now becomes "how do you get the ftp data back into your original program?"

This has come up so often, that the Tk::ExecuteCommand module was developed. Try running your ftp through Tk::ExecuteCommand. You could put your ftp code into a second helper script.

Another option is to use Tk::fileevent (whichs reads files in a non-blocking manner), and use IPC::Open3 to run the ftp stuff. There are other ways to use fileevent too, like the piped form of open. Here is some sample code showing how to integrate IPC::Open3,fileevent, and Tk.

#!/usr/bin/perl -w
use strict 'vars';
#by John Drukman 

$|=1;
use Tk;
use IPC::Open3;
local *IN;
local *OUT;
local *ERR;
my $pid=open3(\*IN,\*OUT,\*ERR,'/bin/bash');
# set \*ERR to 0 to send STDERR to STDOUT 

my $inwin=new MainWindow;
my $entry=$inwin->Entry(-width => 80)->pack;
          $inwin->Button(-text => 'Send',
    -command => \&send_to_shell)->pack;
                                            
my $outwin=new MainWindow;
my $textwin=$outwin->Text(-width => 80,
     -height => 24,
     -state => 'disabled')->pack;
            $outwin->fileevent(OUT,'readable',\&get_from);
MainLoop;

sub send_to_shell {
  my $cmd=$entry->get() . "\n";
  write_textwin("> $cmd");
  print IN $cmd;
}

sub get_from {
  my $buf='';
  sysread OUT,$buf,4096;
  write_textwin($buf);
}

sub write_textwin {
  my $str=shift;
  $textwin->configure(-state=>'normal');
  $textwin->insert('end',$str);
  $textwin->see('end');
  $textwin->configure(-state=>'disabled');
}
__END__
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