Re: EFS 1.6 bug: can't execute shell command on a cray

sandy@ibm550.sissa.it
Mon, 16 May 1994 21:38:03 +0200


Edward,

On Wed, 6 Apr 94 you wrote:

I'm catching up with efs bug reports.

 > I moved a tar file over to my cray account, then couldn't get it to
 > untar. I tried using the ! and entered the command, and got the error
 > listed below.

What error?  Below was only your *ftp ...* buffer.

 > I changed my userid and machine name for security reasons, I hope
 > that's OK.

Yes.  In fact, I prefer it.

dired-do-shell-command (!) isn't really supported for remote systems,
as there is (usually) no way to do a shell command using FTP.  efs has
inherited from ange-ftp a way of doing shell commands using rsh (or
remsh).  This is a bit flakey, through no fault of its own.  The
remsh/rsh protocol is terrible.  No password support; no exit status
support.  Usually, there is a way to get it working by setting up a
.rhost file on the remote host, and maybe fiddling a bit.  If people
have little fixes to improve it, I'll add them, but basically I would
prefer that remote process support eventually branch off into a
separate module from efs.  The utilities required to handle remote
process are different from those for a virtual file system.  Probably
the biggest obstacles to doing this at the moment are the problems
with rsh/remsh.  The PD FTP server available from uunet supports a
"site exec" command, which might eventually be a better way to go.

I'm aware that executing ! on a remote system usually fails in a weird
way.  However, fixing it to at least fail gracefully would probably
interfere with people who have got it to work after a fashion.

--sandy