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

Registered User

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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LEARN ABOUT CENTOS

yum-verify

yum-verify(1)															     yum-verify(1)

NAME

       yum verify plugin

SYNOPSIS

       yum [options] verify [package ...]

DESCRIPTION

       This plugin extends yum with some commands that give verification information on the installed system, much like rpm -V. You can change how
       the verification is done and which files it applies to.

       added yum commands are:
	* verify
	* verify-rpm
	* verify-all

       all of which take the same arguments as the list yum command, obviously you can only verify packages that are installed on the system.

       verify Is the generic verification command, and is intended to give the most useful output. It removes all false matches  due  to  multilib
	      and ignores changes to configuration files by default.

       verify-rpm
	      Is meant to be 100% compatible with rpm -V output, and any differences should be considered as bugs.

       verify-all
	      Is used to list all the differences, including some that rpm itself will ignore.

GENERAL OPTIONS

       These are the options added to yum that are available in the verify commands.  They are:

       --verify-filenames
	      This option is used to limit the filenames that the packages will perform verification.

       --verify-configuration-files
	      This  option is only useful in the generic verify command, and will enable/disable verification of files that are tagged as configu-
	      ration files.

EXAMPLES

       To do the same as rpm -Va, use:

	      yum verify-rpm

       To verify the packages starting with the name yum, use:

	      yum verify 'yum*'

       To verify the binaries that are in a bin directory, use:

	      yum verify --verify-filenames='*bin/*'

       To verify all include files, Eg. for multilib problems, use:

	      yum verify-all --verify-filenames='/usr/include/*'

SEE ALSO

       yum (8)
       yum.conf (5)
       the verify.conf file in /etc/yum/plugins.d

AUTHORS

       James Antill <james.antill@redhat.com>.

BUGS

       Currently yum-verify does not do verify-script checking or dependency checking,
       only file checking.

       Should you find any other bugs, you should first
       consult the FAQ section on http://yum.baseurl.org/wiki/Faq and if unsuccessful
       in finding a resolution contact the mailing list: yum-devel@lists.baseurl.org.
       To file a bug use http://bugzilla.redhat.com for Fedora/RHEL/Centos
       related bugs and http://yum.baseurl.org/report for all other bugs.

James Antill							   01 March 2008						     yum-verify(1)