(PHP 4, PHP 5)

highlight_file -- Syntax highlighting of a file


mixed highlight_file ( string filename [, bool return] )

The highlight_file() function prints out a syntax highlighted version of the code contained in filename using the colors defined in the built-in syntax highlighter for PHP.

If the second parameter return is set to TRUE then highlight_file() will return the highlighted code as a string instead of printing it out. If the second parameter is not set to TRUE then highlight_file() will return TRUE on success, FALSE on failure.

注: The return parameter became available in PHP 4.2.0. Before this time it behaved like the default, which is FALSE

注: Since PHP 4.2.1 this function is also affected by safe_mode and open_basedir.


Care should be taken when using the highlight_file() function to make sure that you do not inadvertently reveal sensitive information such as passwords or any other type of information that might create a potential security risk.

Many servers are configured to automatically highlight files with a phps extension. For example, example.phps when viewed will show the syntax highlighted source of the file. To enable this, add this line to the httpd.conf:

AddType application/x-httpd-php-source .phps

See also highlight_string().

add a note add a note User Contributed Notes
jens dot grasnick at gmail dot com
07-Oct-2006 09:38
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) : $allowedFiles;
file_exists($file)) {
$this -> whitelist[] = $file;
   } else
is_array($allowedFiles) && sizeof($allowedFiles)) {
$this -> addFiles($allowedFiles);
/* for setting new userColors */
public function setColors($newColors = array()) {
$newColors as $key => $color) {
in_array($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\">";
$this -> userColors as $key => $color) {
$color)) {
$nHC = str_replace(sprintf($hTpl, ini_get("highlight.{$key}")), sprintf($hTpl, $color), $nHC);

/* highlight's a string */
public function highlightString($string) {
$hC = "";
$hC = ob_get_contents();
$this -> putColors($hC);
/* highlight's a file */
public function highlightFile($file) {
in_array($file, $this -> whitelist)) {
$this -> highlightString(join("", file($file)));


$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.


= betterHighlighting("test.php", array("comment" => "pink"));

$cl -> highlightFile("test.php");


Have fun.
paul at cheddar dot vaughany dot com
21-Aug-2006 07:53
It's a basic idea but one maybe worth sharing.

switch($_GET['file']) {
header("Location: ".$_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.
showsource at gmail dot com
08-Apr-2006 08:18
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.
marlon at mbwp dot nl
05-Mar-2006 09:06
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.".<br>";
msn at toolskyn dot nl
26-Feb-2006 05:18
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
ganchev at design dot bg
13-Jan-2006 04:40
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


= fopen($_GET['file'], "r");
$count = 1;
$line = "";
while (
$c = fread($f, "1")) {
$line .= $c;
  if (
$c == "\n") {
"<tr style='background: " . (($_GET['line'] == $count) ? "#eedddd" : "#ffffff") . "'><td width='10%'>$count.</td><td>" . highlight_string($line, TRUE) . "</td></tr>\n";
$line = "";

dtroi50 at gmail dot com
10-Jan-2006 06:39
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.

venski at gmail dot com
06-Jan-2006 09:21
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 = $_GET[file];
in_array($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.";     
trukin at gmail dot com
09-Dec-2005 11:46
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.

= array('config.php', 'index.php', 'functions.php');    //array with files to denie
$file = $_GET[file];                    // iniziate the variable
in_array($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.";
// file doesnt exist
echo "That file does not exist.";       
Michael Newton (http://mike.eire.ca/)
07-Dec-2005 01:48
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__ );
Vlad Alexa Mancini valexa at nextcode dot org
22-Feb-2005 03:19
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
aidan at php dot net
26-Sep-2004 11:29
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:

csst0266 at cs dot uoi dot gr
14-Aug-2004 12:42
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.
zan at stargeek dot com
09-Jan-2003 02:24
here's how to use highlight_file to create a browseable archive of php scripts http://www.stargeek.com/scripts.php?script=7&cat=blog