Problem with telnet and paging

[anton]

Hi! First of all, I'm a beginner at perl - so be easy on me :) I'm trying to write a program which uses Net::Telnet to check information on my router (switch (different manufacturers)), and I have a problem with some commands returning a lot of data. I'm using:

my @tmp = $telnet->cmd("sh ver");

It causes a time-out and quits the program. My theory is that the output data is page'd (the switch responds with either "--More--" or "Press c for continous, q for quit, <space> for one more row" and then halts until a char has been pressed. But "->cmd" doesn't issue this, tries to read for X seconds then quits. Is there any way I can tell the Telnet-package to read everything, or do I need to use $telnet->send and $telnet->getline? :< I know that this might be the wrong forum to ask this, but I'm running out of ideas. =) Thanks in advance. Best regards, Anton.

[salva]

Pagging can be disabled on most devices. Just, check the device docs and start the telnet sessions by sending the command that disables it!

[roboticus]

anton:

Salva's suggestion is likely the best way to go. But if you can't disable paging, check out Expect--it's designed for just this type of problem.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

[VinsWorldcom]

With your example "sh ver" command I immediately think Cisco and when I connect to Cisco routers (using Net::Telnet::Cisco by the way, which in turn uses Net::Telnet), I always issue "terminal length 0" as the first command. That disables paging and then long output like 'show ver', 'show run', etc... always work for me.

[anton]

Hi.

Thank you all for your replies. I've looked into the solution with expect - though I don't have the package and the box I'm running the script on is very limited.

The software is indeed Cisco, but my other switches/routes are a different kind (huawei, etc) and they do not have any support for terminal length.

Perhaps my best option would be to use a basic i/o socket, and just read for the '--More--'-line and send a space, or whatnot?

Thanks in advance.

[tbone654]

this works for me on my CISCO's... may be it's the lines...

$telnet->prompt('/\w+# $/');
$telnet->waitfor($telnet->prompt);

that make it work... Don't know, just figuring this out myself...
usage: ./program.pl 10.10.10.77 z.out

#!/usr/bin/perl
use strict;
use warnings;
use Net::Telnet;

my $uri = shift @ARGV or die "IP address needed \n Usage: ./runssh 10.
+10.10.77 outputfile";
my $a = shift @ARGV or die "output file needed \n usage: ./runssh 10.1
+0.10.77 outputfile";

my $telnet = new Net::Telnet  (Timeout=>15
        #,Input_log => "received_data.txt"
        ,Input_log => $a
);


$telnet->open($uri);
$telnet->waitfor('/login: /i');
$telnet->print('Place_the_login_here');
$telnet->waitfor('/Password: /i');
$telnet->print('Place_the password_here');
print "Login is successful \n";
$telnet->prompt('/\w+# $/');
$telnet->waitfor($telnet->prompt);
$telnet->cmd("terminal length 0");
$telnet->cmd("show interface brief");

$telnet->cmd("sh int desc");
$telnet->cmd("sh flogi data");
$telnet->cmd("sh zone act");
$telnet->waitfor($telnet->prompt);

my $out = $telnet->print('exit');
print $out;

$telnet->close();

my $fname = "received_data.txt";

open (my $fh, "<", $fname) or die "Can't open";
while (<$fh>) {
        print if /ip prefix-list/;
        }

[Anonymous Monk]

Even though the switch /router is waiting for a prompt the ---More--- or Press Ctrl+C etc etc, by returning a carriage return or inserting a new line char at the end of your command and the next paged content turns up. Ex: $telnet->cmd('xxxxxxxxxxx'); #If this lines throws an error stating command timed-out, its because your script is waiting for the response from the device you tried to telnet while your device is waiting for a response from the user(Script in this case) which leads to waiting on both the ends and times out. So it can be solved by adding a \n or \t or \r character in the command. Ex: $telnet->cmd('xxxxxxxxxxx\n\r\t');# In this case its similar to the user or script hitting an enter key after the entire command is typed. Now if there are 5 pages in the telnet ouput, append 5 "\n" or "\r" or "\t". Well if there are 7 pages make append count to 7