🚀 go-pugleaf

I remember before  a question was asked about how to delete
a subdirectory in a batch file without stopping.  This case
can be solved well by

ECHO Y |  del subdir.name

Now my question is that I want copy a file to COM1 and 
I do not want batch file to stop.   Since COM1 is not
ready, DOS will pop up something like

Device not ready
Abort, Retry, or Ignore........

I certainly want to abort it in the batch file. But I cannot 
pipeline it as shown in the way to delete subdirectory.

The following is a little background for this.

I am writing a program to collect data from COM1 using Turbo Pascal v5.5.
For some unkown reason, whenever I turn on the PC, I have some magic 
letters in COM1.  Since the interface to COM1 is not written by me, and I also 
do not fully understand the interface part, I cannot strip these
extra letters away.  In the case, my interface part just waiting forever.
I have to reboot the machine.  If the COM1 buffer can be emptied, my 
program works fine.  So, while I am looking for a way to strip away
these extra letters, I can empty the buffer by other programs.  
I tried several other programs, but they all require user input, this 
obviously has nothing to do with my program.  While by mistake, I found
out that copy a file to COM1 can also slove my problem.  
But the problem is still that I have to type an "a" to abort the copy
process since the device is never ready when I turn on the machine (also
because those strange letters).  Thus, I put a line in the batch file

copy autoexec.bat com1

When DOS comes to this line, DOS stops to ask me the input.  How can I
avoid this?  If this cannot be done, how can I write a small program to
empty the communication buffer?