Perl Net::SSH2 Output limit?

Question

I'm stucked on a perl script. It should return me at least 5000 lines that look like this (header just fyi):

Interface         ----- CMTS Measurements -----  --------- CM Measurements ---------                      
(DS-US)           USPwr   USSNR  uReflec Timing  USPwr  DSPwr  DSSNR  uReflec Timing   Last                
S/C/CH-S/CG/CH    (dBmV)   (db)   (dBc)  Offset  (dBmV) (dBmV)  (db)   (dBc)  Offset  Polled MAC address   
----------------- ------- ------ ------- ------  ------ ------ ------ ------- ------- ------ --------------
12/0/8-1/0/0         -0.4   28.3       0 312832    47.0   -2.4   37.2      24 1222.00  00:23 0000.cfbe.9151 (Arris)   
12/0/15-1/0/0         0.0   29.8       0 353280    44.0  -14.4   32.4      30 1380.00  00:22 0017.9635.19b4 (Arris)   
12/0/12-1/0/0         0.4   30.3       0 353024    48.0   -4.5   34.9      30 1380.00  00:22 0017.9795.5d3c (Arris)   
12/0/15-1/0/0        -0.6   28.7       0 357120    44.0    0.2   38.0      30 1396.00  00:20 0017.a6uz.c781 (Arris)   
12/0/14-1/0/0         0.0   28.5       0 354048    45.0    0.2   37.4      25 1383.00  00:20 0017.a289.96ef (Arris)

But somehow the script stops at line 1500... The Script looks like this:

#!/usr/bin/perl -w

use warnings;
use strict;
use Net::SSH2;

my $cmtsip="x.x.x.x";
my $password='somepassword';
my $username="someuser";

# login to cmts and get the table
my $ssh2=Net::SSH2->new();
$ssh2->connect($cmtsip) or die "Unable to connect Host $@ \n";
$ssh2->auth_password($username,$password) or die "Unable to login $@ \n";
my $chan = $ssh2->channel();
$chan->blocking(0);
$chan->shell();

print $chan "show cable modem phy\n";
sleep (40);

while (<$chan>)
{
    print $_;
}

$chan->close;

Can anyone please tell me at which part my script fails?

As it currently is your script fails already while trying to compile. — dgw, Jun 22 '17 at 17:48
I didn't upload the whole script, because the other parts are not relevant. I already have a output on my cli but as i said there's only a part of the lines instead of all of them. — n. traber, Jun 22 '17 at 18:03
Well, to show the problem you should provide a [Minimal, Complete, and Verifiable example](https://stackoverflow.com/help/mcve). So code that won't compile is no help. — dgw, Jun 22 '17 at 19:21

score 0 · Answer 1 · answered Jun 23 '17 at 08:56

I did a test run with your script. It stopped on more prompt

Here slightly modified version of the script, which works fine in my environment:

#!/usr/bin/perl -w

use warnings;
use strict;
use Net::SSH2;

my $cmtsip   = "x.x.x.x";
my $password = 'somepassword';
my $username = "someuser";

# login to cmts and get the table
my $ssh2 = Net::SSH2->new();
$ssh2->connect($cmtsip) or die "Unable to connect Host $@ \n";
$ssh2->auth_password($username, $password) or die "Unable to login $@ \n";
my $chan = $ssh2->channel();
$chan->blocking(0);
$chan->shell();

print $chan "show cable modem phy\n";

read_chanel();

sub read_chanel {
    while (<$chan>) {
        if ($_ =~ /(?m:^\s*--More--)/) {
            print $chan " ";
            return read_chanel();
        }
        print $_;
    } ## end while (<$chan>)
} ## end sub read_chanel

$chan->close;

Beside your question, take a look at Net::SSH2::Cisco or Net::Appliance::Session if you are via SSH dealing with Cisco IOS

Thanks for your answer. I've added your Code to my script but it did not work. The problem is, it's an Arris CMTS and not Cisco hardware. If I connect over ssh from the server (where the script is) towards the CMTS and execute the command "show cable modem phy" I get all the lines I expected. That's the reason I thought about a variable limitation... — n. traber, Jun 27 '17 at 10:22
take a look at [Net::SSH2::Channel](https://metacpan.org/pod/Net::SSH2::Channel#read) read method. It allow you to set buffer size, which could cause your issue — palik, Jun 27 '17 at 12:13

Perl Net::SSH2 Output limit?

1 Answers1