Hi Roger
Thanks for answering. I sent the message a number of times as it was not answered and a huge number of mails came in in the intirim causing my mail to be buried. This lessens the chance of me getting an answer.
The problem I have is that I don't want my password hardcoded anywhere in my scripts (for security). I want to telnet into the host and cd to a directory. So in essence I need to be able to interact with the script mid-script to send in my password and then return the script to doing its business

Here is how it can be done in tcl Expect:


#!/usr/dist/exe/expect -f

set timeout -1
set hostname blah
set login_name blah_blah
spawn $env(SHELL)
match_max 100000
send -- "telnet $hostname\r"
expect "login:"
send -- "$login_name\r"
expect "Password:"
interact -nobuffer -re "(.*)\r" return
#ask user for password and then return to script

send -- "cd $dir\r"
interact
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Now I am trying to translate this into perl (as tcl has some pecularities I don't really like. Heres what I came up with:


#!/usr/bin/perl

use strict;
use Expect;
my $session = new Expect;

my $server_connect = "blah";
my $username = "blah_blah";
my $shell_prompt= '(.*%|.*#|.*>|.*\\$) $';
my $dir="blah_blah_blah";

$session->spawn("bash");

print $session "telnet $server_connect\r";
$session->expect(60, -re, "ogin:");
print $session "$username\r";
$session->expect(10, -re, "assword:");
$session->interact(\*STDIN, "\r");
$session->expect(60, -re, "$shell_prompt");
print $session "cd $dir\r";
$session->interact();
[download]

The problem is that the line:


$session->interact(\*STDIN, "\r");
[download]

does not act in the same way as the line


interact -nobuffer -re "(.*)\r" return
[download]

does in tcl
I was wondering if anyone could elaborate why this is so?
thanks in advance

$exp->expect($timeout,
              [ qr/username: /i, sub { my $self = shift;
                                       $self->send("$username\r");
                                       exp_continue; }],
              [ qr/password: /i, sub { my $self = shift;
                                       $self->send("$password\r");
                                       exp_continue; }],
              $shell_prompt);
[download]

print "username: ";
my $username = <STDIN>;
print "password: ";
my $password = <STDIN>;
chomp $username;
chomp $password;
[download]

my question was to do with the use of the interact command in perl expect. This allows you to interact in real time with the script. I know that I can ask for the variables at the start of the script or even pass them in as parameters but I would like to know why the interact statement that I used does not work as all the documentation on it says it should. Becoming proficient with the expect.pm module means asking questions about some of the apparently unclear aspects of some of its functions

Depending on what you are doing at the remote site, Expect may not be the best solution. Instead of using telnet/Expect, why not use ssh?

Rather than having to handle login character by character yourself, you simply invoke ssh using system(), specifying the account and machine names. Assuming you are connecting to the same machines all the time, you can set up configuration files so that the remote sites know which sites will connect to them. You have to follow some slightly complicated procedure, but the instructions are clear enough.

The result is a configuration where you do not have to specify a password, hence the password does not appear in any script nor in any config file. Since login is based on encryption keys, unauthorized sites are totally blocked. And your code becomes a lot simpler.

If you are connecting to different machines each time, then you will have to provide a password, somehow. But you still gain benefits, your connection will be encrypted, the password will be passed encrypted, not clear-text, to the remote machine.

for anybody who's interested I found out how to do it in perl expect.

$session->interact(\*STDIN, "\r");
print $session "\r";
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is the same as


interact -nobuffer -re "(.*)\r" return
[download]

in tcl expect