PERL Beginners - using system to run ssh $host command

Author

using system to run ssh $host command

Grover Mitchell

2005-08-24, 6:56 pm

Hi,

I am trying to use system to run a command on a remote machine.

system "ssh", $remote_host[0], "sudo", "-u", "nobody",
"/usr/bin/remote_command", "--arg1", $arg1, "--arg2", $arg2;

The problem I run into is that perl will ssh into the remote host and
give me a shell there, instead of running the remote command on the
remote system. When I exit, perl will then try and run the remote
command on my local host. Is there an easy way to accomplish this task
using system?

Thanks for any help.

Wiggins d'Anconia

2005-08-25, 3:55 am

grover mitchell wrote:
> Hi,
>
> I am trying to use system to run a command on a remote machine.
>
> system "ssh", $remote_host[0], "sudo", "-u", "nobody",
> "/usr/bin/remote_command", "--arg1", $arg1, "--arg2", $arg2;
>
> The problem I run into is that perl will ssh into the remote host and
> give me a shell there, instead of running the remote command on the
> remote system. When I exit, perl will then try and run the remote
> command on my local host. Is there an easy way to accomplish this task
> using system?
>
> Thanks for any help.
>

I haven't tested, but there haven't been any other responders yet so I
thought I would chime in.

Have you tried the one argument form of C<system>? There is the
potential for the above to be getting screwed up by the 'exec' rather
than the 'execvp' mentioned in,

perldoc -f system

I suppose. Try joining all of your arguments along with the command into
a single string passed to system and see if that helps. Of course you
could always try Net::SSH::Perl as a substitute.

You also ought to consider using a full path to ssh, and I assume the
above is just a snippet of a larger set of code that does proper error
checking/handling per the C<system> docs ;-)...

HTH,

http://danconia.org

Dhanashri Bhate

2005-08-25, 3:55 am

-> grover mitchell wrote:
-> > Hi,
-> >=20
-> > I am trying to use system to run a command on a remote machine.
-> >=20
-> > system "ssh", $remote_host[0], "sudo", "-u", "nobody",
-> > "/usr/bin/remote_command", "--arg1", $arg1, "--arg2", $arg2;
-> >=20
-> > The problem I run into is that perl will ssh into the=20
-> remote host and
-> > give me a shell there, instead of running the remote command on the
-> > remote system. When I exit, perl will then try and run the remote
-> > command on my local host. Is there an easy way to=20
-> accomplish this task
-> > using system?

Hi,

I had done something like this long back, which works.
so you can try it...

****************************************
*********
$machine=3D"remotemachine";
$prog=3D"/path/to/prog arg1 arg2 arg3";

$remote_command =3D "ssh nobody\@$machine $prog";
system($remote_command);
****************************************
*********

Note: in my case both the machines use NIS.

Hope this helps;

Dhanashri

=20

Pablo Wolter

2005-08-25, 7:59 am

Hi:

Try this:

<variable_to_store> = `rsh -l <username> <hostname> 'command arg1 arg2 ..`;

This works for me, I don't know if this is the best way or if it the more
secure way to run a command in a remore machine, try to search CPAN for a
module that can do something similar.

Pablo.

On 8/24/05, grover mitchell <baguagrover@gmail.com> wrote:
>
> Hi,
>
> I am trying to use system to run a command on a remote machine.
>
> system "ssh", $remote_host[0], "sudo", "-u", "nobody",
> "/usr/bin/remote_command", "--arg1", $arg1, "--arg2", $arg2;
>
> The problem I run into is that perl will ssh into the remote host and
> give me a shell there, instead of running the remote command on the
> remote system. When I exit, perl will then try and run the remote
> command on my local host. Is there an easy way to accomplish this task
> using system?
>
> Thanks for any help.
>
> --
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> For additional commands, e-mail: beginners-help@perl.org
> <http://learn.perl.org/> <http://learn.perl.org/first-response>
>
>
>

--
(o_ Pablo Wolter
//\ Usuario #284649
V_/_ Debian Sid Kernel 2.6.8

Manav Mathur

2005-08-25, 7:59 am

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