Thanks for the quick response Shmem. I should have stated that I had gone through Net::SSH2::Channel and cannot seem to find any argument that allows for the channel to stay open. It seems to me that this is a simple enough request and therefore it should exist somewhere within the module. Has anyone found a way to do this?

It's the shell method of Net::SSH::Channel, as zentara points out below, but alas, his code doesn't seem to work for me.

Seems that this module is somwhat quirky, I could get it work only with some delay between sending a command and reading its output, and then the diamond operator doesn't seem to work on the $chan2 filehandle, but the read method does (linux, perl5.8.8):

#!/usr/bin/perl

use Net::SSH2;

my $ssh2 = Net::SSH2->new();

$ssh2->connect('somehost') or die;

if ($ssh2->auth_password('user','password')) {
    #shell use
    my $chan2 = $ssh2->channel();
    $chan2->shell();
    print $chan2 "uname -a\n";
    select(undef,undef,undef,0.2);
    my ($len, $buf);
    print $buf while ($len = $chan2->read($buf,512)) > 0;
    print $chan2 "who\n";
    select(undef,undef,undef,0.2);
    print $buf while ($len = $chan2->read($buf,512)) > 0;
    $chan2->close;
} else {
    warn "auth failed.\n";
}
[download]

Those selects() could be replaced with calls to $chan2->poll(), which usage to find out is left as an excercise to the reader...

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

#shell use
my $chan2 = $ssh2->channel();
$chan2->shell();
print $chan2 "uname -a\n";
print "LINE : $_" while <$chan2>;
print $chan2 "who\n";
print "LINE : $_" while <$chan2>;
$chan2->close;
[download]

For my code to work, I had to insert a line found in another thread on this wonderful site...



$chan2 = $ssh2->channel();
$chan2->blocking(0);
print $chan2 "tail -5 /var/log/authlog\n";
print "**$_" while <$chan2>;
[download]



Hope this might help somebody else banging their head against the wall as was I.

Well I didn't have to bang my head too long. I just started trying Net::SSH2 a few minutes ago and hit this problem. So I fire up Super Search and there's my answer. Wonderful site, indeed. Perlmonks rocks. And a big ++ to you, vdubjunkie.

That didn't work for me but this does:

$chan2 = $ssh2->channel();
$chan2->blocking(0);
$chan2->exec("tail -5 /var/log/authlog\n");
print "**$_" while <$chan2>;
[download]

Could you show us your code. I've done a lot of development this last year using this module. I believe I used 'shell' when sending commands over the established channel. I don't recall it closing the channel but it's been awhile since I've written code with this module.

I recall having a lot of problems with STDERR and this module. Is this what you are having difficulty with? From the channel module page it says:

shell

Start a shell on the remote host; calls process("shell").

exec ( command )

Execute the command on the remote host; calls process("exec", command). Note that only one of these requests can succeed per channel (cp. "exec" in perlfunc); if you want to run a series of commands, consider using shell instead.


I recommend 'shell'. It worked well for me. Post the code and we'll check it out.

BTW, while this module is still immature IMO (not even at 1.0 I think). David has done a fantastic job and it's far better than the original NET::SSH::PERL IMO. I've been able to hit a couple hundred Unix/Linux servers in a few minutes and run inventory reports. It's very speedy and does a great job. We're now using it to create user accounts and set passwords in minutes rather than days.

Yeah it's archaic but we can't decide how to tie everything together with LDAP and I was tired of waiting for management to approve funding :-)

Sorry for the delay in getting back to you. Apologies I just could not get to a computer yesterday. The Code I was using was the one taken from the perlmonks web-site.

my $chan2 = $ssh2->channel();
$chan2->shell();
print $chan2 "hostname -a\n";
print "LINE : $_" while <$chan2>;
print $chan2 "tail -f /var/adm/messages";
print "LINE : $_" while <$chan2>;
$chan2->close;
[download]

(In fact I tried various options on that perlmonks page without success.) The only difference being the "tail -f" command I used instead of "uname" or "who". I notice when I do a "tail -50000". The channel would stay open for as long as it took to get through the 50000 lines. So there is no problem with keeping the channel open as such.I think the problem lies when it is being an interactive real-time command like "tail -f" or "snoop" when I want to keep the channel up and for some reason it takes a snap-shot,or what's in it's buffer and then closes. Any help, greatly appreciated !!!!!!!!!!!!!!!!!!!!!!!. U235sentinel have you ever come across this before?. Regards, Shooter

I think the reason that Net::SSH::Perl::Buffer was slow was that the compression level might have been too high. You can use Net::SSH::Perl::Comp to set the compression level lower. For example,

my $comp = Net::SSH::Perl::Comp->new('Zlib',1);

sets the compression level to 1, the valid levels being 0 to 9. The default is 5.

Hello everyone I have been trying to use this kind of scripts to connect to a remote machine and execute some commands. I think the connection is well done, but the execution of commands is not working for me. This particular case is about: 1.- I connect via ssh to a linux machine 2.- I enter in a special mode with MML commands (machine to man language) typing 'mml' 3.- I do staff with this mml commands My script is failing in step 2. I just want to send this "mml" and it's not working :( :(

if( $ssh2->connect($host) ) {
  if( $ssh2->auth_password($user,$pass) ) {
print "connected.....\n";
        #shell use
        my $chan = $ssh2->channel();
        $chan->blocking(0);
        $chan->shell();
        print "sending command....\n";

            
    my $num = 10;
    while($num--){
    sleep(1);
    }
    
    print $chan "mml\n";
    select(undef,undef,undef,0.2);
    print $buf while ($len = $chan>read($buf,512)) > 0;
[download]

I tried with several methods: print $chan, exec ('comand'), everything in this thread... but still not working. Any idea?