I agree with the others regarding using the Net::telnet module if you can afford to. I know that the implementation may be a bit more complicated, but you have less of a chance of having unexpected things happen in your script. For your case you would need to do something like this

use Net::Telnet;  # initialize the telnet module
my $username = 'user';
my $password = 'some_password';
my $command = 'ls -la';
print "enter the full domain name or IP of the machine that you want t
+o telnet to\n";
chomp(my $host=<STDIN>);

my prompt_regex = '/
                    .*   
                     (        
                      \-?\@?  
                       \w*?\s?  
                       [\$#\%>~] 
                       \]?                      
                       |                       
                       \\\[\\e\[0m\\\] \[0m    
                       )                      
                       \s?    
                       /x';  

$shell = new Net::Telnet ('Timeout'=>'7',
    'Errmode'=> sub { report_error("login failure"); },
    'Prompt' => $prompt_regex );

$shell->open(Host=>$host);    # opens the object
$shell->login($username,$password);   # login 

# then we issue some command with
$shell->cmd("$command");

# or get the output of some command
my $cmd_output = $shell->cmd("$command");

# and close the telnet object
sleep 1;
$shell->close;

sub report_error
{
   .... some code here to handle errors....
}
[download]

To give due credit, the above code is from a project that a friend and I work on for fun known as the Temerity Project. Though we both contributed to this script, he refined its implementation and added that awesome regular expression to check for a user's prompt type.
We originally tried using the expect.pm for interacting with telnet. This works too but is a lot more messy.
I hope that this is at least a bit of a help. The Net::Telnet module is a very nice module should you decide to use it. Take care, Joe