Unable to store the command output from Net::SSH2. Please help.

[perl514]

Venerable Monks,

I am trying to collect the ouptut of a command that is run after logging in to a NAS Array through SSH.

The command,  nas_server -list gives the statuts of the NAS Array. I am trying the following script to do it. For some reason, its not capturing the actual command output of the command in the  @output array even after stating  my @output = $chan->exec('nas_server -list'); It seems to capture the value 1, which I presume corresponds with the successful status of the command being executed.

Here is the complete script

#!/usr/bin/perl;
use Modern::Perl;
use 5.014;
use Net::SSH2;

my $nasip = '127.0.0.1'; #Actul IP is different. 

my $user = 'user';

my $pass = 'passwd';

my $ssh = Net::SSH2->new();

$ssh->debug(1);

say "Connecting to $nasip";

$ssh->connect("$nasip") || warn "$!";

$ssh->auth_password("$user","$pass");

my $chan = $ssh->channel();

my @output = $chan->exec('nas_server -list');

say "output is: @output";

$chan->close();

And here is the output. The IP given in the example is 127.0.0.1, but I am actually using a different IP to login to the NAS Array

Connecting to 127.0.0.1
libssh2_channel_open_ex(ss->session, pv_channel_type, len_channel_type
+, window_size, packet_size, ((void *)0) , 0 ) -> 0x11353dc
output is: 1
Net::SSH2::Channel::DESTROY
Net::SSH2::DESTROY object 0x9b745c

Firstly, I know very rudimentary Perl and I am back here after almost a year, so if any mistakes in the script above please do forgive me. Thanks a lot to vdubjunkie, because If not for his node Net::SSH2 woes, I wouldn't even have written the above script.

The NAS Array (Network Attached Storage Array) is an EMC Storage Array - NS960. I am running the script from a Windows 2003 host on which Perl Version 5.14.2 is installed.

Kindly request you please guide me to a site where a detailed tutorial for the Net:SSH2 Module is given. I did go through the perldoc, also googled, but didn't find anything that I could understand. :(

[salva]

Net::SSH2::Channel::exec does not capture the output of the remote command, it just launches it. You have to use the read method afterward to retrieve the output.

On Unix/Linux systems Net::OpenSSH is far easier to use. Or there is also Net::SSH::Any that can work on top of Net::SSH2 and provides a simpler to use API, though it is still not a mature module.

[syphilis]

Based on what works for me on Windows (connecting to a linux server) you should be able to do:

my @output;
$chan->blocking(1);
$chan->exec('nas_server -list');
while (<$chan>) {push @output, $_}
print for @output;

Cheers,
Rob

[perl514]

Hi Salva,

Thanks for the update, but I cannot download any extra modules, because the system from which I am running the perl scripts is not connected to the internet. I am using DWIM Perl and it only has Net::SSH2.

Hi Syphilis (Rob),

I did try your suggestion, but that still doesnt work. All I got is whats shown below

Connecting to xxx.xxx.xxx.xxx
libssh2_channel_open_ex(ss->session, pv_channel_type, len_channel_type
+, window_size, packet_size, ((void *)0) , 0 ) -> 0x1137a74
Net::SSH2::poll: timeout = 250, array[1]
- [0] = channel
- [0] events 1
- libssh2_poll returned 1
- [0] revents 128
Net::SSH2::Channel::DESTROY
Net::SSH2::DESTROY object 0x9b7404

Any suggestion to a good tutorial for Net::SSH2 will really help.

[salva]

Well, Net::SSH::Any has no dependencies besides Net::SSH2, so it should be pretty easy to install, even without internet access. Just unpack its lib directory in the right place under the DWIN directory and you are done!

[perl514]

Hi

Tried using the Net::SSH::Any module, but it's not doing what I expected. I am going wrong somewhere.

I am trying to ssh into the VMWare Guest OS (CentOS 6.2). Before trying the script, I pinged and ensured that its working. I am also able to putty into the VMWare Guest OS, but not able to use the script for some reason.

Given below is the script

#!/usr/bin/perl
use Modern::Perl;
use Net::SSH::Any;

my $host = '192.168.247.101';
my $user = "perl514";
my $passwd = "redhat";
my $ssh = Net::SSH::Any->new ($host, user => $user, password => $passw
+d);
my @output = $ssh->capture2("ls -l");
say "@output";

And here is the output. The cursor blinks for a while so it appears that it could be running the command, but returns the following error

Use of uninitialized value $output[0] in join or string at anyping.pl 
+line 10.

Basically I want to capture the output of the ls -l command in the @output.