Who spot the trick?

use strict;
use warnings;
my @unv;
my $pos;

while (<DATA>){push @unv,$.-1,$.,$.+1 if /XXXXX/;$pos=(tell DATA)-leng
+th $_ unless $pos}

seek DATA,$pos,0;


while (<DATA>) {print unless $.-__LINE__ ~~ @unv}
__DATA__
XXXXX
Aoooo
XXXXX is my name
Boooo
11111
22222
33333
Coooo
XXXXX is what I play
Doooo
44444


# OUTPUT

11111
22222
33333
44444

[download]
If you spot the trick please explain it to... me!
L*

UPDATE: the trick can be avoided with a cleaner solotion assigning to $. 
use strict;
use warnings;

my @unv;
my $pos;

while (<DATA>){push @unv,$.-1,$.,$.+1 if /XXXXX/;$pos=(tell DATA)-leng
+th $_ unless $pos}
seek DATA,$pos,0;

$.=0;
while (<DATA>) {print unless $. ~~ @unv}

[download]

L*

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

In reply to Re^2: how to check for a word in a file... -- who spot the trick? by Discipulus
in thread how to check for a word in a file and if found remove that line, the above line and the below line from the file. by Ganesh Bharadwaj1

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