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Full Discussion: Killing an Xterm while leaving subprocess alive...
Top Forums Shell Programming and Scripting Killing an Xterm while leaving subprocess alive... Post 87282 by mschwage on Friday 21st of October 2005 09:40:20 PM
Old 10-21-2005
Killing an Xterm while leaving subprocess alive...
Hi,
I'm not quite understanding what I'm doing (happens often). This pseudocode works:

#!/bin/pseudoksh

function kill_parent {
when i_want_to ; do
sleep 2
kill -TERM $PPID
exit
done
}

kill_parent &
ssh remote_host sh <<-EOF
notify_kill_parent # let the bg function know it's ok to kill parent
run_command # something x-based
EOF


Now, if I start my script in an xterm:
xterm -e run_my_script
It works as expected! The xterm pops up, ssh queries me for a password, the command runs and displays, and, seconds later, the xterm is killed. This is what I want to have happen. But I'm not sure why the remote shell and my application (run_command, above) still stick around. I've been pretty sloppy with stdin/stdout so I'm surprised they don't disappear when I kill the parent (xterm).

I'm happy it works, but I'm worried about a bug creeping in later- for example, since I'm not handling stdout, am I in danger of filling a buffer that is going to make the app hang? Or something like this.

I'm looking for insight into what happens when xterm calls ssh which calls a shell which calls a command. Xterm dies but the command does not. Why?
Thanks.
-Schwage
 

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LEARN ABOUT DEBIAN

gnome-ssh-askpass

GNOME-SSH-ASKPASS(1)					      General Commands Manual					      GNOME-SSH-ASKPASS(1)

NAME

       gnome-ssh-askpass - prompts a user for a passphrase using GNOME

SYNOPSIS

       gnome-ssh-askpass

DESCRIPTION

       gnome-ssh-askpass  is  a GNOME-based passphrase dialog for use with OpenSSH.  It is intended to be called by the ssh-add(1) program and not
       invoked directly.  It allows ssh-add(1) to obtain a passphrase from a user, even if not connected to a terminal (assuming that an X display
       is  available).	This happens automatically in the case where ssh-add is invoked from one's ~/.xsession or as one of the GNOME startup pro-
       grams, for example.

       In order to be called automatically by ssh-add, gnome-ssh-askpass should be installed as /usr/bin/ssh-askpass.

ENVIRONMENT VARIABLES

       The following environment variables are recognized:

       GNOME_SSH_ASKPASS_GRAB_SERVER
	      Causes gnome-ssh-askpass to grab the X server before asking for a passphrase.

       GNOME_SSH_ASKPASS_GRAB_POINTER
	      Causes gnome-ssh-askpass to grab the mouse pointer using gdk_pointer_grab() before asking for a passphrase.

       Regardless of whether either of these environment variables is set, gnome-ssh-askpass will grab the keyboard using gdk_keyboard_grab().

AUTHOR

       This manual page was written by Colin Watson <cjwatson@debian.org> for the Debian system (but may be used by others).  It was based on that
       for x11-ssh-askpass by Philip Hands.

															      GNOME-SSH-ASKPASS(1)
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