use strict;
use warnings;
use Tie::File;
sub max ($$) { $_[$_[0] < $_[1]] }
sub min ($$) { $_[$_[0] > $_[1]] }
my $file_in = 'data.txt';
my @lines;
tie @lines, 'Tie::File', $file_in or die "Unable to tie $file_in $!";
my $n_recs = @lines; # how many records are in the file?
my @lnbrs = ();
my $i = 0;
while ($i < $n_recs - 1) {
    my $twolines = $lines[$i] . $lines[$i + 1];
    if ($twolines =~ m/file\s+for\s+(?:bankrup|chapter)/im) {
        push @lnbrs, $i
    }
    $i++;
}

foreach my $ln (@lnbrs) {
    my $start = max($ln-3, 0);
    my $end = min ($ln+3, $n_recs);
    <strong class="highlight">print</strong> '-' x 75, "\n";
    foreach ($start .. $end) {
        <strong class="highlight">print</strong> "$lines[$_]\n";
    }
}
untie @lines;