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Full Discussion: while loop stops after first iteration - remote ssh exit command problem?
Top Forums Shell Programming and Scripting while loop stops after first iteration - remote ssh exit command problem? Post 302597268 by jelloir on Thursday 9th of February 2012 08:56:59 PM
Old 02-09-2012
Thanks chihung, I tried your suggestion but it still fails, so the exit doesn't appear to be the problem. If I check the return value from the ssh command it is 0, so i'm stumped? Thanks for the IFS suggestion.

The script currently looks like this:

Code:
#!/bin/bash

mxg_hosts_file="/etc/mxg/ssh-hosts"

while IFS=":" read mxg_host mxg_port ; do
    echo "Connecting and Upgrading ${mxg_host}"
    ssh root@${mxg_host} -p ${mxg_port} 'aptitude update && aptitude safe-upgrade -y && shutdown -r now'
done < ${mxg_hosts_file}

Edit - figured it out.

You have to use ssh's -n argument.

Code:
 -n      Redirects stdin from /dev/null (actually, prevents reading from
             stdin).  This must be used when ssh is run in the background.  A
             common trick is to use this to run X11 programs on a remote
             machine.  For example, ssh -n shadows.cs.hut.fi emacs & will
             start an emacs on shadows.cs.hut.fi, and the X11 connection will
             be automatically forwarded over an encrypted channel.  The ssh
             program will be put in the background.  (This does not work if
             ssh needs to ask for a password or passphrase; see also the -f
             option.)

Last edited by jelloir; 02-09-2012 at 10:03 PM..
 

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LEARN ABOUT DEBIAN

ssh-askpass-fullscreen

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

NAME

       ssh-askpass-fullscreen - A simple replacement for ssh-askpass written with gtk2

SYNOPSIS

       ssh-askpass-fullscreen

DESCRIPTION

       This manual page was written for the Debian distribution because the original program does not have a manual page.

       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 auto-matically 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, ssh-askpass-fullscreen should be installed as /usr/bin/ssh-askpass

       ssh-askpass-fullscreen is a program that...

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 will be grabbed too.

       These  may have some benefit to security if you don't trust your X server. Keyboard is always grabbed.

       SEE ALSO
	      ssh-add(1), ssh-askpass(1).

AUTHOR

       This manual page was written by Marco Presi (Zufus) <zufus@debian.org>, for the Debian GNU/Linux system (but may be used by others) and	it
       is based on that for x11-ssh-askpass by Philip Hands and the one for gnome-ssh-askpass by Colin Watson <cjwatson@debian.org>

								   May 8 , 2004 					 SSH-ASKPASS-FULLSCREEN(1)
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