#!/bin/perl

use strict;
use warnings;

my $input_file = 'input.txt';

open(my $in_file,'<',$input_file) or die "Can not open file $input_file for reading: $!.\n";

while (<$in_file>) {
    if (/Friday/) {
        warn "match on line $.\n"; # warn goes to STDERR
    } elsif ($. == 2) {            # no match on line 2
        chomp;                     # remove line ending
        $_ .= "Friday\n";          # add "Friday" and line ending
        warn "added 'Friday' to line $.\n";
    }
    print;
}

close($in_file);