The actual reason that the mail isn't being sent is that you are not telling the sendmail what to do, you have neither told it the recipient on the command line nor specified the -t switch to get it to obtain the recipient from the headers of the message you are piping in.

If you set your $sendmail variable to:

/usr/lib/sendmail -oi -t
[download]

Then it should work.

That all said I think you are almost certainly better off using one of the NMS programs to do this, not least because they are probably more secure than you will ever make your own program and also because they are well supported.

But I would say that.

/J\