ssh session hangs while running cmd on remote server

Christopher Faylor
Thu May 31 20:27:00 GMT 2007

On Thu, May 31, 2007 at 04:08:02PM -0400, Larry Hall (Cygwin) wrote:
>KenLee wrote:
>>I'm a Linux newbie, so please excuse my dumb questions.
>>Installed cygwin successfully on a box running Win2003 server.  When I
>>ssh to it to run a VB script file (.kcu extension) as "cmd /c
>>update.kcu", my client session just hangs until I press Ctrl-C.
>>Meanwhile on the remote server, nothing happens.
>>However, if I run cygwin directly on the box and enter the exact same
>>command, the script file runs no problem.
>>Any help would be most appreciated.
>See what the "CYGWIN" environment variable is set to in both cases.  If
>the 'ssh' session has 'tty', you'll want to remove that.  It's probably
>in the server's startup environment.  If having 'tty' set is the
>problem, you should be able to reproduce it by running the same script
>from 'rxvt'.

There seems to be some confusion about the CYGWIN tty setting.

The only time it should have any effect is when there is a console involved.
In that scenario, what effectively happens is that CYGWIN opens up a pty
and pretends that the pty is a linux-like tty.

Setting CYGWIN=tty for servers should be a no-op.  Ditto, having it set
while operating under a pty or if there is no console associated with the

So, if setting CYGWIN=tty actually causes a problem in an ssh session
then that is probably a Cygwin bug.  Until that problem has become evident
lets not assume that there is a problem.

I don't mean to be picking on you Larry.  You are not the only person
I've seen opine about CYGWIN=tty .  I remain unconvinced that setting it
would present a problem other than the standard problem of running pure
Windows programs under a Cygwin pty.


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