use strict;
use warnings;

use IO::Select;

my $cmd = '"cat /etc/passwd"';
my $login = 'usr@host';
my $pkey = "$ENV{HOME}/.ssh/privateKey";

my @shell = ( '/usr/bin/ksh' => (
	-c => $cmd,
));

my @sshcmd = ('/usr/bin/ssh' => (
	-t => (),
	-v => (),
	#-vv => (),
	#-vvv => (),
	-i => $pkey,
	-o => 'StrictHostKeyChecking no',
	$login,
	@shell,
));

open (IFILE, '-|') || exec @sshcmd;

my $select = IO::Select->new();
$select->add(\*IFILE);

my @ready;
while ( @ready = $select->can_read(5) ) {
	foreach my $fh (@ready) {
		my $line = <$fh>;
print STDERR "line=$line";
		if(eof($fh)) {
			$select->remove($fh);
			close($fh) || warn "Close problem on fh: $fh";
		}
	}
}

close(IFILE);

END{
	print STDERR "\$!: $!\n";
}