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 PHP

ldap_connect

LDAP_CONNECT(3) 							 1							   LDAP_CONNECT(3)

ldap_connect - Connect to an LDAP server

SYNOPSIS

       resource ldap_connect NULL ([string  $hostname], [int  $port = 389])

DESCRIPTION

	Establishes a connection to a LDAP server on a specified $hostname and $port.

PARAMETERS

	      o $hostname
		- If you are using OpenLDAP 2.x.x you can specify a URL instead of the hostname. To use LDAP with SSL, compile OpenLDAP 2.x.x with
		SSL support, configure PHP with SSL, and set this parameter as ldaps://hostname/.

	      o $port
		- The port to connect to. Not used when using URLs.

RETURN VALUES

	Returns a positive LDAP link identifier on success, or FALSE on error. When OpenLDAP 2.x.x is used, ldap_connect(3) will always  return  a
       resource  as it does not actually connect but just initializes the connecting parameters. The actual connect happens with the next calls to
       ldap_* funcs, usually with ldap_bind(3).

	If no arguments are specified then the link identifier of the already opened link will be returned.

EXAMPLES

       Example #1

	      Example of connecting to LDAP server.

	      <?php

	      // LDAP variables
	      $ldaphost = "ldap.example.com";  // your ldap servers
	      $ldapport = 389;		       // your ldap server's port number

	      // Connecting to LDAP
	      $ldapconn = ldap_connect($ldaphost, $ldapport)
			or die("Could not connect to $ldaphost");

	      ?>

       Example #2

	      Example of connecting securely to LDAP server.

	      <?php

	      // make sure your host is the correct one
	      // that you issued your secure certificate to
	      $ldaphost = "ldaps://ldap.example.com/";

	      // Connecting to LDAP
	      $ldapconn = ldap_connect($ldaphost)
			or die("Could not connect to {$ldaphost}");

	      ?>

SEE ALSO

       ldap_bind(3).

PHP Documentation Group 													   LDAP_CONNECT(3)