See open or IPC::Open3. With either, you can work interactively with the ssh process. But I recommend either launching Perl on the other side or launching a single process on the other side which produces all its output, so you should just do:

my $output = `ssh $host '$command'`;
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Having worked (and still work) within the constraints of a "prod environment", I can appreciate the issue, but I must ask for some details:

1. Is the constraint just for prod, ie can you test this in dev/test and then promote the code into production?
• Reason: if this is the case, then go the correct route and install the Net::SSH module and follow the proper promotion procedure.
2. Is it just a limitation of technology (ie proxy), permissions (no root) or process (not allowed) that you can't install modules?
• Reason: If it's a permissions issue, you can install the modules in your home directory for example, and "use lib" those modules, or you can download them directly from CPAN and install them manually if a proxy is the issue.

You can open an ssh connection with a pipe:

my ($user, $host) = ('me', 'host.domain');
open my $SSH, '|-', 'ssh', join '@', $user, $host;
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Then you can send commands to ssh with print:

print $SSH "mv *.back backups/";
print $SSH "echo 'Moved backups' >> log";
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So far, the system(); menthod has been giving me troubles. Does anybody know the trick ?

It's hard to imagine what troubles you are having. system works perfectly well for this and there isn't any trick involved. If you go into a bit more detail than just "giving me troubles" then I'm sure any of us could point you in the right direction.

Sorry to hear about the prohibition of modules.