Tip of the day - USER command

[Bill Vermillion]

On Fri, Mar 19, 2004 at 10:12:44PM -0600, Jerry Rains thus spoke:
> On Friday 19 March 2004 19:10, Bob Stockler wrote:
> > On Fri, Mar 19, 2004 at 02:50:52PM -0600, Jerry Rains wrote:
> > | Sent: Friday, March 19, 2004 2:33 PM
> > | Subject: Re: Tip of the day - USER command

> > | > Jerry Rains wrote: > I've been working with the USER
> > | > command a lot recently and was having > problems with
> > | > it either hanging or blowing up. I determined that if >
> > | > the user presses Break just before the USER command was
> > | > written to, > it caused > filePro to exit to the shell.

> > | > Ken Brody wrote:

> > | > Only if your USER program exits when break is pressed.

> > | That's the problem. It does, but it isn't my program and I
> > | don't have the source code so I can't fix it.

> > Bob Stockler wrote:
> > What it you moved it to another name and wrote a shell
> > script wrapper for it where you trapped the INT signal ???

> I guess a little more information is in order.
> /var/scripts/pcms is a shell wrapper for a customized version
                                             ^^^^^^^^^^
> of 'netcat' that Brian White wrote. It tunnels to a Windows box
> and connects to PC*Miler/CONNECT on port 8145. I tried adding
> 'trap "" 2' to the pcms shell script, but that didn't help. I
  ^^^^^^^^^^^^^
> think that 'netcat' is really the problem but it could also be
> 'CONNECT' in PC*Miler.

There is more than one program called 'netcat' floating around.
Sources are available.  But without access to Brian's changes you
will have no idea what his customization has done to the code, so
what works for a plain version of netcat make not work in the
customized version.  O'Briens version has always been called
'netcat' but his documenation refers to it as 'nc', and his
distribution is nc110.  If you have questions why not email Brian?

While a version that is called netcat is documented as being called
with the name of 'ncat'.   The 'nc' above is often has it's binary
named 'netcat' - so you can see the confusion.

'ncat' was written because the author didn't like the
bi-directional feature of 'nc'

I just checked the sources and the version commonly known as
'netcat' [nc] does trap SIGINT, SIGQUIT, and SIGTERM, so unless that
has been modified your trap 2 in your script is redundant.

You could compile a stock version to see if the trouble persist,
but i'ts a pretty rugged program and you may be chasing the wrong
thing.    I have often thought problems were in something I could
not control, only to look further and find my own stupid mistrake.

Bill

-- 
Bill Vermillion - bv @ wjv . com