#!/usr/bin/perl

while(<DATA>){
@contents = grep { !/IT/ } $_;
print @contents;
}
__DATA__
Economic slow down in IT
HI
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When you say the word "IT" do you really mean "IT" as a word? It is important:

use strict;
use warnings;

while(<DATA>) {
    print if /IT/
}
__DATA__
This is IT for now
Nothing of interest here
Looping is used for ITeration
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gives:

This is IT for now
Looping is used for ITeration
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However if we use the word boundary anchor \b:

while(<DATA>) {
    print if /\bIT\b/
}
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we only get

This is IT for now
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You should reall really read perlintro

while(<DATA>){
    next if /IT/;
    print;
}
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