Here's the complete example of the script:

#!/usr/bin/perl
use strict;
use warnings;
use IO::Pty::Easy;

# Get stdin when this char is found (Telnet).
$/ = "\n";
# Autoflush, write without buffering (Telnet).
$| = 1;

# Main loop.
undef $_;
my $quit = 0;
my $input;
my $pty = IO::Pty::Easy->new();
do {
    $input = <STDIN>;
    # Remove trailing new line character.
    $input =~ s/\r//g;
    $input =~ s/\n//g;
    eval {
        if ($input =~ /quit/) {
            $quit = 1;
        }
        elsif ($input =~ /run/) {
            my $st = $pty->spawn("/usr/bin/omshell");
            die "Cannot run /usr/bin/omshell" unless ($st);
        }
        else {
            reply(help());
        }
    };
    reply($@) if ($@);
    print "> ";
} while (!$quit);

sub help {
#---------------------------------------------------------------------
+---------|
    return qq{
quit

run
    Launch app over IO::Pty::Easy.
    };
}

# Reply to user.
sub reply {
    print shift, "\n";
}
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If you run that with xinetd you will find out that subprocess cannot be launched.