use IPC::Open2;

my($rdh, $wrh);
my $pid = open2($rdh, $wrh, "telnet", "192.168.1.1");
[download]

Makeshifts last the longest.

Tell me, what am I doing wring here...

open(PIPE, "telnet 192.168.1.1 |") or die $!;
while (<PIPE>) {
    $bah = $_;
    $bah =~ s/192.168.1.1//;
    print $bah;
 }
close(PIPE);

bash~$ perl test.pl
Trying ...
Connected to .
Escape character is '^]'.
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Locks up before it gets to the login prompt....

 use IPC::Open2;
 
    print open2(\*IN, \*OUT, "telnet 10.65.2.252");
 
    print OUT "Trying\n";
 
    while (<IN>) {
        $_ =~ s/10.65.2.252//;
        print;
    }
    close IN;
    close OUT;

bash~$ perl test1.pl
26210Trying ...
Connected to .
Escape character is '^]'.
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Does the same thing in the same place, with the exception of printing the pid.

Am I misunderstanding what can and can't be done here?

All I need to do is just strip off that ip address, or the whole "trying" message, during execution.( these snips do that, but hang up in the same place ).

What you are likely running into is that telnet is an interactive application. The buffering that Perl does to read input by lines destroys the interactivity. When the user hits the first key of their username, they expect to see it echoed immediately. But Perl is still sitting there waiting for the end of the line. Luckily, you only need to process the header. Once you finish reading the header, you can stop reading line by line. Either enter a loop that reads and writes a single character. Or find some way to reconnect the telnet stdout to the Perl stdout.

I'm not sure what you mean by hanging. Do you mean it's not terminating? If so, do you know where it's stuck? Most likely, since the remote host hasn't closed the connection and therefor telnet is still running and hasn't closed the IN handle, while(<IN>) is blocked waiting for data. I also don't see any attempt at actually sending a command to the remote host. Is the user supposed to type that in? You'd have to do that yourself in that case. Are you printing a command but nothing happens? In that case you probably haven't read Suffering from Buffering.

Also, it seems you haven't quote understood what the file handles do - or is Trying a command on the remote machine? That is the only reason you should be printing it to OUT, but it doesn't seem likely to me.

Makeshifts last the longest.

Some relevant code might be helpful, i can't see what you're actually doing.

... program I've called with back ticks ...

Well the `backticks` return the ouput of the program, you can modify this output and then print it to STDOUT. Where's the problem?

Did you consider using open() to fork off telnet and process its output line by line and just in time? What do you mean with "loosing control of telnet"?

I have an script that works as an interactive menu, some of the choices require the script to telnet to a remote host for the user to login to and complete a task, when they are done, it takes them back to the menu. What I'm trying to do is prevent the user from seeing this:

Trying 192.168.1.1...
Connected to 192.168.1.1.
Escape character is '^]'.
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Or at least the ip address, when the script calls 'telnet 192.168.1.1'.

Does this make more sense?

I think I would still use Net::Telnet, and build an interactive shell into your script that passes on the user entered data on via Net::Telnet to the remote shell. See PPM on ActivePerl and CPAN (the module) for examples of what I'm thinking of. Also check out the module Term::ReadLine, which modern versions of CPAN.pm use, to write the command line interface for this side.

Oh, look, no code. But you didn't provide any code either, so I won't feel bad about it. :-)

Does this make more sense?

No, i still can't find any code in your post. What do you mean with "call" when you say "the script calls 'telnet ...'"?

Maybe you want to have a look at Expect, but I'm still just guessing.

--
http://fruiture.de

machine:~ > telnet hostname 25
Trying 192.168.0.1...
Connected to hostname.
Escape character is '^]'.
220 hostname.domain ESMTP Postfix
QUIT
221 Bye
Connection closed by foreign host.

compare to:

machine:~ > telnet hostname 25 | tail +4
220 hostname.domain ESMTP Postfix
QUIT
Connection closed by foreign host.
221 Bye