#! perl
use strict;
use warnings;

my @block;
my $in_block = 0;

while (<DATA>)
{
    if    (/^interface/)
    {
        push @block, $_;
        $in_block = 1;
    }
    elsif ($in_block)
    {
        if    (/^!/)
        {
            print for (@block, $_);
            @block    = ();
            $in_block = 0;
        }
        elsif (/^\s*shutdown/)
        {
            @block    = ();
            $in_block = 0;
        }
        else
        {
            push @block, $_;
        }
    }
}

__DATA__


# contents of file:
!
blah
!
blah
blah
!
# start to grab section here with start (/interface/)
interface GigabitEthernet1/1/2
 description PC Trunk
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 100
 switchport mode trunk
 queue-set 2
 priority-queue out 
 mls qos trust dscp
 storm-control broadcast level 1.00
 storm-control multicast level 1.00
 spanning-tree guard loop
 channel-protocol lacp
 channel-group 1 mode active
! 
# ^ end section with (/!/)
# ignore entire block of data when after (/interface/) a (/shutdown/) is seen before (/!/)"
interface GigabitEthernet1/1/3
 shutdown
!
interface GigabitEthernet1/1/4
 shutdown
!
interface TenGigabitEthernet1/1/1
!
interface TenGigabitEthernet1/1/2

##</code><code>##

22:16 >perl 1563_SoPW.pl
interface GigabitEthernet1/1/2
 description PC Trunk
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 100
 switchport mode trunk
 queue-set 2
 priority-queue out
 mls qos trust dscp
 storm-control broadcast level 1.00
 storm-control multicast level 1.00
 spanning-tree guard loop
 channel-protocol lacp
 channel-group 1 mode active
!
interface TenGigabitEthernet1/1/1
!

22:16 >