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PHP : Function Reference : Miscellaneous Functions : highlight_file


Syntax highlighting of a file (PHP 4, PHP 5)
mixed highlight_file ( string filename [, bool return] )

Code Examples / Notes » highlight_file

michael newton

To print out the current file:
<?php highlight_file( __FILE__ ); ?>
Useful to add this as a header to all scripts (during development only, of course!)
if ($_GET['debug']) {
   highlight_file( __FILE__ );


To add line numbers to source code, with optional function linking, use the below function:
A much more thorough and smarter, though slower version is here:


this function can be a high security risk. use something like in_array to check if a file is prohibited to be shown on screen.
$ar= array('config.php', 'index.php', 'functions.php'); //array with files to denie
$file = $_GET[file]; // iniziate the variable
if(!in_array($file, $ar)){ // check if it is prohibited
highlight_file($file); //highlight file
}else{ // prohibited file
echo "You do not have permision to see the ".$file." file.";
}else{ // file doesnt exist
echo "That file does not exist.";


Please, be aware of just using marlon at mbwp dot nl example to show the sourcecode
Do as told in this manual, "CAUTION", do some check on what code to highlight.
Simply just using $_GET["file"] is very bad.


It's a basic idea but one maybe worth sharing.
switch($_GET['file']) {
case 1:
case 2:
case 3:
header("Location: ".$_SERVER["PHP_SELF"]);
Save the script as showfile.php and access it like this:
<a href="showfile.php?file=1">Click here to see file 1 source code</a>
The default case is for people editing the URL to try to access further files. Just don't add any files you don't want users to see, and maybe hard-code in large, random numbers or MD5 hashes.


If you run a site that has PHP script examples and you want to show the source, instead of a phps file, just add the following code to the top of the script.
if(count($_GET)) {
Then to make a source link use this:
print'<a href="?source">Show source</a>';
Note that you don't have to use souce. If any get variables are set, it'll work.


I use this (simple and dirty) function in my tutorials to add linenumbers. I let all the linenumbers in one table cell so it is easier for people to copy and paste the code (so they don't have to remove all the linenumbers):
function highlight_with_linenum($file)
//open handle, set vars
$handle = fopen($file, "r");
$count = 1;
$lines = "";
//look line ends
while ($thisone = fread($handle, "1"))
if ($thisone == "\n")
//add number
$lines .= $count . "<br />";
//close handle
//highlight contents
$contents = highlight_file($file, TRUE);

//print output (you could as well return now)
print '<table><tr><td><code>' .
 $lines . '</code></td><td>' .
 $contents . '</td></tr></table>';
Maybe it's of use to someone


I use the folowing code to highlight a file with line numbers:
echo "<table bgcolor=#EEEEEE><tr><td width=30>";
for ($i = 1; $i <= count(file($_GET['file'])); $i++) echo $i.".
echo "</td><td>";
echo "</td></tr></table>";


I think it will be better if the variable contains the files that are allowed to be viewed. There can always befound a way to pass the name of a forbiddedn file that is not in the prohibited array.
Thus the code will be:
//array with files to allow
$allowed = array('index.php', 'menu.php', 'about.php');
// get the filename
$file = $_GET[file];
   if(in_array($file, $allowed)){
       // check if it is part of the allowed list
       highlight_file($file); //highlight file
       // not allowed. just die. do not warn ;)
   // file doesnt exist
   echo "The file does not exist.";      


i much prefer to use the .phps extension for showing highlighted source. all you have to do is type "cp example.php example.phps" at the command line.
on the flip side, for easy dynamic source sharing, it's as simple as:
if (!isset($_GET['file']) || trim($_GET['file']) == '') {
   echo 'please pass me something yummy';
if (!file_exists($_GET['file'])) {
   echo "<b>{$_GET['file']}</b> does not seem to exist :(";

jens dot grasnick

Hi there, i build a "little" class to controll the highlighting functions (highlight_source & highlight_file) of PHP a little bit more. You can:
- set the highlighting colors without rewrite your php.ini
-create a whitelist using by highlightFile - so your're surly that nobody take a look on your private source ;-)
- work with the highlighted content - it returns the highlighted content, not show it like highlight_file or highlight_source did.
class betterHighlighting {
 /* user colors */
 private $userColors = array(
  "string"  => "",
  "comment" => "",
  "keyword" => "",
  "bg"      => "",
  "default" => "",
  "html"    => "",
 /* array of allowed file for using by ::highlightFile() */
 private $whitelist = array();
 /* construct */
 function __construct($allowedFiles = NULL, /* array or NULL */
                      $newColors    = NULL  /* array or NULL */) {
   /* add (if some given) files to the highlighting whitelist */
   if($allowedFiles) {
     $this -> addFiles($allowedFiles);
   /* set highlighting colors */
   if($newColors) {
     $this -> setColors($newColors);
 /* for adding files to the whitelist */
 public function addFiles($allowedFiles /* array or string */) {
   $file = is_array($allowedFiles) ? array_pop($allowedFiles) : $allowedFiles;
   if(file_exists($file)) {
     $this -> whitelist[] = $file;
   } else
   if(is_array($allowedFiles) && sizeof($allowedFiles)) {
     $this -> addFiles($allowedFiles);
   return void;
 /* for setting new userColors */
 public function setColors($newColors = array()) {
   foreach($newColors as $key => $color) {
     if(in_array($key, array_keys($this -> userColors))) {
       $this -> userColors[$key] = $color;
 /* replaces default colors with users colors */
 private function putColors($highlightedContent) {
   $nHC = $highlightedContent;
   $hTpl = "<span style=\"color: %s\">";
   foreach($this -> userColors as $key => $color) {
     if(!empty($color)) {
       $nHC = str_replace(sprintf($hTpl, ini_get("highlight.{$key}")), sprintf($hTpl, $color), $nHC);
   return $nHC;
 /* highlight's a string */
 public function highlightString($string) {
   $hC = "";
   $hC = ob_get_contents();
   return $this -> putColors($hC);
 /* highlight's a file */
 public function highlightFile($file) {
   if(in_array($file, $this -> whitelist)) {
     return $this -> highlightString(join("", file($file)));
   return "";
$cl = new betterHighlighting([mixed files], [mixed colors]);
To put a file or a array of files to the whitelist, use (void)  ::addFiles(mixed files).
To set a new color for highlighting use (void) ::setColors(array("string" => ..., "comment" => ..., "keyword" => ..., "bg" => ..., "default" => ..., "html" => ...)).
You only have to give the keyword(s), which color you'll change. If you only want to change the color of the highlighted comments, call ::setColors(array("comment" => "newcolor")) and so on.
Highlighting String:
(string)::highlightString(string $source)
Highlighting File:
(string)::highlightFile(string $file)
Note: The two last function RETURNS the highlighted content, not shows it directly.
Little example: I want to highlight the file "test.php" and the comments should be pink.
$cl = betterHighlighting("test.php", array("comment" => "pink"));
echo $cl -> highlightFile("test.php");
Have fun.


here's how to use highlight_file to create a browseable archive of php scripts


here's a simple way to add line numbers and
optionally highlight the one that has error on it.
just pass file and line arguments as GET variables
$f = fopen($_GET['file'], "r");
$count = 1;
$line = "";
echo "<table>";
while ($c = fread($f, "1")) {
 $line .= $c;
 if ($c == "\n") {
   echo "<tr style='background: " . (($_GET['line'] == $count) ? "#eedddd" : "#ffffff") . "'><td width='10%'>$count.</td><td>" . highlight_string($line, TRUE) . "</td></tr>\n";
   $line = "";
echo "</table>";


Here's a better take at highlighting a file with line numbers:
<style type="text/css">
.num {
float: left;
color: gray;
text-align: right;
margin-right: 6pt;
padding-right: 6pt;
border-right: 1px solid gray;}
function highlight_num($file)
 echo '<code class="num">', implode(range(1, count(file($file))), '<br />'), '</code>';
Thanks for the implode() part from Arevos at

vlad alexa mancini valexa

Here is a small bash script that you can type at the console to make recursive symbolic .phps links for all your .php files starting at your curent directory
for f in `find -name '*.php'`; do ln -s `basename $f` $f's'; done
NOTE: You doubtedly want to do this at / as it will make such symlinks for all the php files on your filesystem
NOTE: This places the symlinks in the same directory as the php file that they are simlinking
And a simpler one that is not recursive and does the same thing but only for the php files in your current directory
for f in *.php; do ln -s $f $f's'; done


Here is a simple, yet useful, tip... Issuing the following command under a Unix-like OS:
ln -s your_script.php your_script.phps
Will result in the creation of a symbolic link (called your_script.phps) to the source code (your_script.php). This way you have (apart from the source code .php) the highlighted version of your script (.phps) accessible via your web browser.


A function which parses the output of highlight file and replaces &lt;span&gt; wits &lt;a&gt;, replaces the style="color: #XXXXXX" part with class="cX", storing the colors in some css rules; that way you get a smaller output size (ratio is about about 1.2 ~ 1.4):
function highlight_file2($fl,$ret){
if(!isset($ret)) $ret = false;
$str = highlight_file($fl,true);
preg_match_all("/\<span style=\"color: #([\d|A|B|C|D|E|F]{6})\"\>.*?\<\/span\>/",$str,$mtch);
$m = array_unique($mtch[1]);
$cls = '<style type="text/css">'."\n";
$rpl = array("</a>");
$mtc = array("</span>");
$i = 0;
foreach($m as $clr) {
$cls .= "a.c".$i."{color: #".$clr.";}\n";
$rpl[] = "<a class=\"c".$i++."\">";
$mtc[] = "<span style=\"color: #".$clr."\">";
$cls .= "</style>";
$str2 = str_replace($mtc,$rpl,$str);
if($ret) return $str2;
else echo $str2;

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