问grep正则表达式匹配并打印更多行，但如果额外行包含不同的模式，则忽略打印(或不匹配)

EN

use v5.20.0;  # signatures requires perl >= 5.20
use feature qw(say);
use strict;
use warnings;
use experimental qw(signatures);

{
    my $lines = read_file('file.txt');
    for my $i (0..$#$lines) {
        my $line = $lines->[$i];
        if ($line =~/\b(gloom)\b/) {
            if (!match_second_pattern($lines, $i)) {
                print_block($lines, $i);
            }
        }
    }
}

sub print_block($lines, $i) {
    my $N = $#$lines;
    for my $j (0..2) {
        last if $i+$j > $N;
        print $lines->[$i+$j];
    }
}

sub match_second_pattern($lines, $i) {
    my $N = $#$lines;
    return 0 if ($i + 2) > $N;
    return $lines->[$i+2] =~ /elsewhere/;
}

sub read_file( $fn ) {
    open ( my $fh, '<', $fn ) or die "Could not open file '$fn': $!";
    my @lines = <$fh>;
    close $fh;
    return \@lines;
}

#!/usr/bin/perl
 
use strict;
 
my $s = "If the line was there is a loom in the gloom
would you want that line printed?
Just trying to understand if you're just
other than as part of gloom
if you really do want to exclude lines
even when loom appears on it's own elsewhere on the line";
 
while ($s =~ /^.*?\bgloom\b(?!.*\n.*\n.*?\belsewhere\b).*\n.*\n.*\n?/mg) {
    print "$&";
}

#!/usr/bin/perl -w
use strict;

my $s = '';
# read from stdin or the file specified on the command line:
while (<>) {
    $s .= $_ ;
}

while ($s =~ /^.*?\bgloom\b(?!.*\n.*\n.*?\belsewhere\b).*\n.*\n.*\n?/mg) {
    print "$&";
}

grep -oPzn '(?m)^.*?\bgloom\b(?!(?:.*\R){2}.*?\belsewhere\b)(?:.*\R){2}.*\R?' file > outputfile

#!/bin/bash
s="If the line was there is a loom in the gloom
would you want that line printed?
Just trying to understand if you're just
other than as part of gloom
if you really do want to exclude lines
even when loom appears on it's own elsewhere on the line"
grep -oPzn '(?m)^.*?\bgloom\b(?!(?:.*\R){2}.*?\belsewhere\b)(?:.*\R){2}.*\R?' <<< "$s"