Ideally, you should be able to run commands sequentially:

my $output1 = $ssh->capture('sh run');
my $output2 = $ssh->capture('sh ver');
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Unfortunately, some devices do not support this mode of operation and force you to talk to some kind of custom shell.

In that case, in order to start a remote shell from Net::OpenSSH, call open2pty without passing any command:

my ($pty, $pid) = $ssh->open2pty;
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...and then, use Expect to talk to the shell.

Sometimes the following approach also works:

my $output = $ssh->capture({stdin_data => "ssh ver\nexit\n"})
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See also the FAQ section from the module docs.