Bash - here document on RHEL 6.8 and 6.9 servers aren't working Post: 303040553

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Top Forums UNIX for Beginners Questions & Answers Bash - here document on RHEL 6.8 and 6.9 servers aren't working Post 303040553 by greavette on Thursday 31st of October 2019 11:50:49 AM

10-31-2019

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Bash - here document on RHEL 6.8 and 6.9 servers aren't working

H Forum,

I was thankful in getting help from this post that allowed me to connect to multiple severs at once using here documents to gather data into variables. But I've discovered that the same bash command that works on my RHEL 7 servers do not work on RHEL 6? What's strange about my problem is that I'm not getting an error either. The problem is that the variables return empty when I try the following code on RHEL 6.8 or 6.9 servers we manage:

Code:

IFS=$'\t' read FLAVOUR HOSTNAME ACTIVE_KERNEL INACTIVE_KERNEL UPTIME <<- EOFREAD
        $ssh -qo StrictHostKeyChecking=no -o ConnectTimeout=1 user@$InputIP sudo -u user sh -s <<- EOFSSH | tr $'\n' $'\t'
        exec bash
        cat /etc/redhat-release 2>/dev/null || lsb_release -a 2>/dev/null | grep Description | cut -f2
        awk -F= '/^NAME/{print $2}' /etc/os-release 2>/dev/null || grep Red |cat /etc/redhat-release 2>/dev/null || lsb_release -a 2>/dev/null | grep Description | cut -f2
        hostname
        uname -r
        rpm -qa | grep '^kernel-[0-9]' |grep -vE `uname -r` | paste -sd \; || echo "Can't List Ubuntu Kernels"
        uptime | cut -d "," -f1
        exit
EOFSSH
        )
EOFREAD

I've thought of adding in the ability to determine if my server is RHEL 6 or 7 using code like the following:

python -mplatform | grep -qi red &&

but even if I could determine RHEL version I'm still not sure why my RHEL 6 servers do not return variable data back. I've tested this above code connecting to just one server to try and triage the issue. No errors are returned. the variable fields are just empty. Whereas on my RHEL 7 servers I return back variables with no issue. Could it be that how I use Here Documents just doesn't work with RHEL 6 servers? has anyone seen this before?

I've also tested connecting to a RHEL 6 server multiple times to get the data I need. what I mean by this is instead of connecting to a RHEL 6 server once and collecting data I've tested connecting to a RHEL 6 for each command I need so connecting multiple times and there are no issues with the above commands I'm issuing.

Perhaps I'll just need to identify RHEL 6 servers and gather their data differently than I do for RHEL 7 severs but before I do that I thought I would check this forum for any advice first.

Thank you.

greavette

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bashbug

BASHBUG(1)						      General Commands Manual							BASHBUG(1)

NAME

       bashbug - report a bug in bash

SYNOPSIS

       bashbug [--version] [--help] [email-address]

DESCRIPTION

       bashbug	is  a shell script to help the user compose and mail bug reports concerning bash in a standard format.	bashbug invokes the editor
       specified by the environment variable EDITOR on a temporary copy of the bug report format outline. The user must fill  in  the  appropriate
       fields  and  exit  the  editor.	 bashbug  then	mails the completed report to bug-bash@gnu.org, or email-address.  If the report cannot be
       mailed, it is saved in the file dead.bashbug in the invoking user's home directory.

       The bug report format outline consists of several sections.  The first section provides information about the  machine,	operating  system,
       the  bash  version, and the compilation environment.  The second section should be filled in with a description of the bug.  The third sec-
       tion should be a description of how to reproduce the bug.  The optional fourth section is for a proposed fix.  Fixes are encouraged.

ENVIRONMENT

       bashbug will utilize the following environment variables if they exist:

       EDITOR Specifies the preferred editor. If EDITOR is not set, bashbug defaults to emacs.

       HOME   Directory in which the failed bug report is saved if the mail fails.

       TMPDIR Directory in which to create temporary files and directories.

SEE ALSO

       bash(1)

AUTHORS

       Brian Fox, Free Software Foundation
       bfox@gnu.org

       Chet Ramey, Case Western Reserve University
       chet@po.cwru.edu

GNU Bash-4.0							   1998 July 30 							BASHBUG(1)