#!/usr/bin/perl -w
use strict;

local $/=undef;
my @objects;

# check for basic syntax
if ($#ARGV < 0)
    { die "Usage: program.pl file.text\n"; }

my $rgxpar = qr{(^begin\n(\d+)\n.*?^end$)}mos;

open (FILNAM, '<', $ARGV[0])
    or die "Can't open $ARGV[0] for reading.\n";
my $allfile = <FILNAM>;
close FILNAM
    or die "Can't close $ARGV[0] for reading.\n";

while ($allfile =~ /$rgxpar/g)
    {
    my $objectref = 'ref' . $2;
    if ($1 =~ /bar/ ) { push (@objects, $objectref); }
    }

for (@objects)
    {
    $allfile =~ s/^ *(foo)? +$_\n//mn;
    }

open ( OUTFIL, '>', "$ARGV[0].removed")
    or die "Can't open $ARGV[0].removed for writing.\n";
print OUTFIL $allfile;
close OUTFIL
    or die "Can't close $ARGV[0].removed for writing.\n";
[download]