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Full Discussion: While loop is causing ssh command to exit from script after first iteration.
Top Forums Shell Programming and Scripting While loop is causing ssh command to exit from script after first iteration. Post 302949532 by kchinnam on Monday 13th of July 2015 12:55:57 AM
Old 07-13-2015
While loop is causing ssh command to exit from script after first iteration.
I am trying to check multiple server's "uptime" in a loop over "ssh".
When I execute multiple ssh commands with hard coded servernames script is executing fine.

But when I pass server names using while loop, script is exiting after checking first server's status, why?

Code:
# serverList
serverA
serverB
serverC

Code:
# checkServerStatus.sh
#!/bin/bash

# This block got executed fine without exiting from script.
ssh serverA uptime
ssh serverB uptime
ssh serverC uptime

# This block is exiting from script after executing ssh once with serverA.
while read server; do
        ssh $server uptime
done < serverList

Code:
> 
# output 
$> bash -xv ./test.sh
#!/bin/bash

ssh serverA uptime
+ ssh serverA uptime
 04:38am  up 39 days  0:23,  1 user,  load average: 0.00, 0.02, 0.05
ssh serverB uptime
+ ssh serverB uptime
 04:38am  up 38 days 22:40,  0 users,  load average: 0.01, 0.04, 0.05
ssh serverC uptime
+ ssh serverC uptime
 04:38am  up 39 days  5:47,  0 users,  load average: 0.00, 0.01, 0.05


while read server; do
        ssh $server uptime
done <serverList
+ read server
+ ssh serverA uptime
 04:38am  up 39 days  0:23,  1 user,  load average: 0.00, 0.02, 0.05
+ read server

If I comment "ssh $server uptime" and simply print it "echo ssh $server uptime", while loop is not exiting.

How can I fix this or work around this?
Last edited by kchinnam; 07-13-2015 at 01:57 AM.. Reason: indentation
 

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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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