PHP to search within txt file and echo the whole line

<?php
$file = 'somefile.txt';
$searchfor = 'name';

// the following line prevents the browser from parsing this as HTML.
header('Content-Type: text/plain');

// get the file contents, assuming the file to be readable (and exist)
$contents = file_get_contents($file);

// escape special characters in the query
$pattern = preg_quote($searchfor, '/');

// finalise the regular expression, matching the whole line
$pattern = "/^.*$pattern.*\$/m";

// search, and store all matching occurences in $matches
if (preg_match_all($pattern, $contents, $matches))
{
   echo "Found matches:\n";
   echo implode("\n", $matches[0]);
}
else
{
   echo "No matches found";
}

<?php
$searchthis = "mystring";
$matches = array();

$handle = @fopen("path/to/inputfile.txt", "r");
if ($handle)
{
    while (!feof($handle))
    {
        $buffer = fgets($handle);
        if(strpos($buffer, $searchthis) !== FALSE)
            $matches[] = $buffer;
    }
    fclose($handle);
}

//show results:
print_r($matches);
?>

<?php
// What to look for
$search = 'foo';
// Read from file
$lines = file('file.txt');
foreach($lines as $line)
{
  // Check if the line contains the string we're looking for, and print if it does
  if(strpos($line, $search) !== false)
    echo $line;
}

<?php
$search = 'foo';
$lines = file('file.txt');
// Store true when the text is found
$found = false;
foreach($lines as $line)
{
  if(strpos($line, $search) !== false)
  {
    $found = true;
    echo $line;
  }
}
// If the text was not found, show a message
if(!$found)
{
  echo 'No match found';
}

$needle = "blah";
$content = file_get_contents('file.txt');
preg_match('~^(.*'.$needle.'.*)$~',$content,$line);
echo $line[1];

if (isset($_GET["keyword"])){

   foreach(glob('*.php') as $file) { 

      $searchfor = $_GET["keyword"];
      
      // the following line prevents the browser from parsing this as HTML.
      header('Content-Type: text/plain');
      
      // get the file contents, assuming the file to be readable (and exist)
      $contents = file_get_contents($file);
      // escape special characters in the query
      $pattern = preg_quote($searchfor, '/');
      // finalise the regular expression, matching the whole line
      $pattern = "/^.*$pattern.*\$/m";
      // search, and store all matching occurences in $matches
      if(preg_match_all($pattern, $contents, $matches)){
         echo "Found matches:\n";
         echo $file. "\n";
         echo implode("\n", $matches[0]);
         echo "\n\n";
      }
      else{
      //  echo "No matches found";
      }
   }
}