#!/usr/bin/perl

use strict;
use warnings;

$/ = "!\n";
while( <DATA> )
  {
  /^interface (.*\n)(?: .*\n)*? spanning-tree guard root/ and print $1
+;
  }

__DATA__
!
interface other-one
 switchport access vlan 300
 switchport mode access
 switchport port-security maximum 130
 switchport port-security
 switchport port-security aging time 2
 switchport port-security aging type inactivity
 no logging event link-status
 speed 100
 duplex full
 srr-queue bandwidth share 1 60 30 10
 srr-queue bandwidth shape 3 0 0 0
 mls qos trust device cisco-phone
 storm-control broadcast level pps 1k
 storm-control multicast level pps 2k
 storm-control action shutdown
 storm-control action trap
 spanning-tree portfast
 spanning-tree bpduguard enable
!
!
interface FastEthernet1/0/3
 switchport access vlan 300
 switchport mode access
 switchport port-security maximum 130
 switchport port-security
 switchport port-security aging time 2
 switchport port-security aging type inactivity
 no logging event link-status
 speed 100
 duplex full
 srr-queue bandwidth share 1 60 30 10
 srr-queue bandwidth shape 3 0 0 0
 mls qos trust device cisco-phone
 storm-control broadcast level pps 1k
 storm-control multicast level pps 2k
 storm-control action shutdown
 storm-control action trap
 spanning-tree portfast
 spanning-tree bpduguard enable
 spanning-tree guard root
!
!
interface other-two
 switchport access vlan 300
 switchport mode access
 switchport port-security maximum 130
 switchport port-security
 switchport port-security aging time 2
 switchport port-security aging type inactivity
 no logging event link-status
 speed 100
 duplex full
 srr-queue bandwidth share 1 60 30 10
 srr-queue bandwidth shape 3 0 0 0
 mls qos trust device cisco-phone
 storm-control broadcast level pps 1k
 storm-control multicast level pps 2k
 storm-control action shutdown
 storm-control action trap
 spanning-tree portfast
 spanning-tree bpduguard enable
!
!
interface FastEthernet1/0/4
 switchport access vlan 300
 switchport mode access
 switchport port-security maximum 130
 switchport port-security
 switchport port-security aging time 2
 switchport port-security aging type inactivity
 no logging event link-status
 speed 100
 duplex full
 srr-queue bandwidth share 1 60 30 10
 srr-queue bandwidth shape 3 0 0 0
 mls qos trust device cisco-phone
 storm-control broadcast level pps 1k
 storm-control multicast level pps 2k
 storm-control action shutdown
 storm-control action trap
 spanning-tree portfast
 spanning-tree bpduguard enable
 spanning-tree guard root
!

[download]

Outputs: 

FastEthernet1/0/3
FastEthernet1/0/4

[download]

In reply to Re: search for a string and return previous relating string if found by tybalt89
in thread search for a string and return previous relating string if found by Anonymous Monk

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