Here are a few more pointers:

To explore your original problem, I refactored your code into the style that I would write (except that I would go further to use some template module). I include it below, in case anyone finds it useful. 

#!/usr/bin/env perl
use strict;
use warnings;
use Carp;

my $prestring = '???';
$prestring = '.'; # Overridden for PerlMonks testing

my $wanted_string = 'apple'; # really take from param 'sitem';

my $index_dir = $prestring;
my @book_indexes_titles = (
    [ '1800.txt'   , '1800: Mechanical Movements, Powers and Devices, 
+1911' ],
    [ '507.txt'    , '507: Five Hundred and Seven Mechanical Movements
+. 1893' ],
    [ '970.txt'    , '970: Mechanical Appliances, Mechanical Movements
+ and Novelties of Construction. 1904' ],
    [ 'ACAM.txt'   , 'ACAM: Appletons Cyclopedia of Applied Mechanics,
+ 1880 ' ],
    [ '???.txt'    , 'Audels Carpenters and Builders Guide I' ],
    [ '???.txt'    , 'Audels Carpenters and Builders Guide II' ],
    [ '???.txt'    , 'Audels Carpenters and Builders Guide III' ],
    [ '???.txt'    , 'Audels Carpenters and Builders Guide IV' ],
    [ 'AMOM.txt'   , 'AMOM: A Manual of Mending and Repairing. 1907' ]
+,
    [ '???.txt'    , 'Farm Blacksmithing (1901)' ],
    [ 'FCOA.txt'   , 'FCOA: Farmers Cyclopedia of Agriculture. 1911' ]
+,
    [ 'FCOLS.txt'  , 'FCOLS: Farmers Cyclopedia of Live Stock. 1908' ]
+,
    [ 'FDAD.txt'   , 'FDAD: Furniture Design and Draughting. 1900' ],
    [ '???.txt'    , 'ICS Reference 14' ],
    [ '???.txt'    , 'Pottery for /artists, Craftsmen, and Teachers (1
+930)' ],
    [ '???.txt'    , 'Practical Poultry Production (1910)' ],
    [ 'TJCB.txt'   , 'TJCB: Thomas Jeffersons Cook Book. 1937' ],
    [ 'TMOL.txt'   , 'TMOL: The Making of Leather. 1914' ],
    [ 'TPSD.txt'   , 'TPSD: The Practical Stock Doctor. 1912' ],
    [ 'TSC.txt'    , 'TSC: The Settlement Cookbook. 1903' ],
    [ 'TSI.txt'    , 'TSI: The Shoe Industry. 1916' ],
    [ '???.txt'    , 'Univeral Household Assistant (1884)' ],
    [ 'VIRG.txt'   , 'VIRG: Virginia Housewife or Methodical Cook. 189
+9' ],
    [ 'WBH.txt'    , 'WBH: Window Blinds. 1907. (Hasluck)' ],
    [ '???.txt'    , 'Wood Finishing, 1903' ],
    [ 'WHCB.txt'   , 'WHCB: White House Cook Book. 1887' ],
    [ 'WWM.txt'    , 'Windmills and Wind Motors, 1910' ],
    [ 'YCMI.htm'   , 'YCMI: You Can Make It. 1929-1931' ],
    [ 'YOUNGS.htm' , 'YOUNGS: Youngs Demonstrative Translation of Scie
+ntific Secrets. 1861' ],
);

sub search_the_file {
    croak("Wrong number of arguments") if @_ != 2;
    my ( $fh, $search_string ) = @_;

    my $search_qm = quotemeta $search_string;
    my $search_re = qr{$search_qm}i; # i for insensitive-to-case

    my @found;
    while (<$fh>) {
        chomp;
        push @found, $_ if uc($_) =~ /$search_re/;
    }

    return @found;
}

my $separator_line
    = '<center><img border="0" src="/article_separator.png"></center><
+br>'
    . "\n";
$separator_line = "---\n"; # Overridden for PerlMonks testing


my $count_total = 0;

BOOK:
for my $book_aref (@book_indexes_titles) {
    my ( $index_file, $book_title ) = @{$book_aref};

    print $separator_line;

    open my $fh, '<', "$index_dir/$index_file" or do {
        print "<center>ATOCI not found for book <b>$book_title</b></ce
+nter><br>\n";
        next BOOK;
    };

    my @lines = search_the_file( $fh, $wanted_string );

    close $fh;

    $count_total += scalar @lines;

    print "<center><b>$book_title</b></center><br>\n";
    for my $line (@lines) {
        print "<center>$line</center><br>\n";
    }
}

print $separator_line;
print "$count_total records found.<br>\n";
print $separator_line;

[download]

In reply to Re: losing html in print calling function. by Util
in thread losing html in print calling function. by Librum

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
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