Ruby
  IO.foreach('logs1.txt') {|x| puts x if /\b\w{15}\b/.match? x }

  Python3
  import re
  with open('logs1.txt', 'rt') as fh:
      for line in fh:
          if re.search(r'\b\w{15}\b', line): print(line, end=' ')

  Perl
  open my $fh, '<', 'logs1.txt';
  while (<$fh>) { chomp; say if $_ =~ /\b\w{15}\b/; }
  close $fh;  
  
  NodeJS
  var fs = require('fs'), byline = require('byline');
  var stream = byline(fs.createReadStream('logs1.txt', {encoding: 'utf8'}));
  stream.on('data', function(line) { if (line.match(/\b\w{15}\b/)) console.log(line); });

  PHP
  $fh = fopen('logs1.txt', 'r');
  while (($line = fgets($fh)) !== false) {
    if (preg_match('/\b\w{15}\b/', $line)) echo $line;
  }
  fclose($fh);