吴裕雄--天生自然PHP-MySQL-JavaScript学习笔记：实用PHP技术

<?php
  $month = 9;    // September (only has 30 days)
  $day   = 31;   // 31st
  $year  = 2018; // 2018

  if (checkdate($month, $day, $year)) echo "Date is valid";
  else echo "Date is invalid";
?>

<?php // testfile.php
  $fh = fopen("testfile.txt", 'w') or die("Failed to create file");

  $text = <<<_END
Line 1
Line 2
Line 3
_END;

  fwrite($fh, $text) or die("Could not write to file");
  fclose($fh);
  echo "File 'testfile.txt' written successfully";
?>

<?php
  $fh = fopen("testfile.txt", 'r') or              
    die("File does not exist or you lack permission to open it");

  $line = fgets($fh);
  fclose($fh);
  echo $line;
?>

<?php
  $fh = fopen("testfile.txt", 'r') or
    die("File does not exist or you lack permission to open it");

  $text = fread($fh, 3);
  fclose($fh);
  echo $text;
?>

<?php // copyfile.php
  copy('testfile.txt', 'testfile2.txt') or die("Could not copy file");
  echo "File successfully copied to 'testfile2.txt'";
?>

<?php // copyfile2.php
  if (!copy('testfile.txt', 'testfile2.txt'))
    echo "Could not copy file";
  else echo "File successfully copied to 'testfile2.txt'";
?>

<?php // movefile.php
  if (!rename('testfile2.txt', 'testfile2.new'))
    echo "Could not rename file";
  else echo "File successfully renamed to 'testfile2.new'";
?>

<?php // deletefile.php
  if (!unlink('testfile2.new')) echo "Could not delete file";
  else echo "File 'testfile2.new' successfully deleted";
?>

<?php // update.php
  $fh   = fopen("testfile.txt", 'r+') or die("Failed to open file");
  $text = fgets($fh);

  fseek($fh, 0, SEEK_END);
  fwrite($fh, "$text") or die("Could not write to file");
  fclose($fh);

  echo "File 'testfile.txt' successfully updated";
?>

<?php
  $fh = fopen("testfile.txt", 'r+') or die("Failed to open file");
  $text = fgets($fh);

  if (flock($fh, LOCK_EX))
  {
    fseek($fh, 0, SEEK_END);
    fwrite($fh, "$text") or die("Could not write to file");
    flock($fh, LOCK_UN);
  }

  fclose($fh);
  echo "File 'testfile.txt' successfully updated";
?>

<?php
  echo "<pre>"; // Enables display of line feeds
  echo file_get_contents("testfile.txt");
  echo "</pre>"; // Terminates pre tag
?>

<?php
  echo file_get_contents("http://oreilly.com");
?>

<?php // upload.php
  echo <<<_END
    <html><head><title>PHP Form Upload</title></head><body>
    <form method='post' action='upload.php' enctype='multipart/form-data'>
    Select File: <input type='file' name='filename' size='10'>
    <input type='submit' value='Upload'>
    </form>
_END;

  if ($_FILES)
  {
    $name = $_FILES['filename']['name'];
    move_uploaded_file($_FILES['filename']['tmp_name'], $name);
    echo "Uploaded image '$name'<br><img src='$name'>";
  }

  echo "</body></html>";
?>

<?php //upload2.php
  echo <<<_END
    <html><head><title>PHP Form Upload</title></head><body>
    <form method='post' action='upload2.php' enctype='multipart/form-data'>
    Select a JPG, GIF, PNG or TIF File:
    <input type='file' name='filename' size='10'>
    <input type='submit' value='Upload'></form>
_END;

  if ($_FILES)
  {
    $name = $_FILES['filename']['name'];

    switch($_FILES['filename']['type'])
    {
      case 'image/jpeg': $ext = 'jpg'; break;
      case 'image/gif':  $ext = 'gif'; break;
      case 'image/png':  $ext = 'png'; break;
      case 'image/tiff': $ext = 'tif'; break;
      default:           $ext = '';    break;
    }
    if ($ext)
    {
      $n = "image.$ext";
      move_uploaded_file($_FILES['filename']['tmp_name'], $n);
      echo "Uploaded image '$name' as '$n':<br>";
      echo "<img src='$n'>";
    }
    else echo "'$name' is not an accepted image file";
  }
  else echo "No image has been uploaded";

  echo "</body></html>";
?>

<?php // exec.php
  $cmd = "dir";   // Windows
  // $cmd = "ls"; // Linux, Unix & Mac

  exec(escapeshellcmd($cmd), $output, $status);

  if ($status) echo "Exec command failed";
  else
  {
    echo "<pre>";
    foreach($output as $line) echo htmlspecialchars("$line\n");
    echo "</pre>";
  }
?>

<?php
  echo "<pre>"; // Enables viewing of the spaces

  // Pad to 15 spaces
  printf("The result is $%15f\n", 123.42 / 12);

  // Pad to 15 spaces, fill with zeros
  printf("The result is $%015f\n", 123.42 / 12);

  // Pad to 15 spaces, 2 decimal places precision
  printf("The result is $%15.2f\n", 123.42 / 12);

  // Pad to 15 spaces, 2 decimal places precision, fill with zeros
  printf("The result is $%015.2f\n", 123.42 / 12); 

  // Pad to 15 spaces, 2 decimal places precision, fill with # symbol
  printf("The result is $%'#15.2f\n", 123.42 / 12); 
?>

<?php
  echo "<pre>"; // Enables viewing of the spaces

  $h = 'Rasmus';

  printf("[%s]\n",        $h); // Standard string output
  printf("[%12s]\n",      $h); // Right justify with spaces
  printf("[%-12s]\n",     $h); // Left justify with spaces
  printf("[%012s]\n",     $h); // Zero padding
  printf("[%'#12s]\n\n",  $h); // Use the custom padding character '#'

  $d = 'Rasmus Lerdorf';

  printf("[%12.8s]\n",    $d); // Right justify, cutoff of 8 characters
  printf("[%-12.12s]\n",   $d); // Left justify, cutoff of 12 characters
  printf("[%-'@12.10s]\n", $d); // Left justify, pad '@', cutoff 10 chars
?>

来源：https://www.cnblogs.com/tszr/p/12380930.html

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