header location error redirecting - php

Question

Hello I am trying to read a file which contain a url where I want to redirect I am using this
$file = 'test.txt';
$myfile = fopen($file, "r") or die("Unable to open file!");
$link = fread($myfile,filesize($link));
fclose($myfile);
header("Location: $link");
The browser show me an error "The Page isn´t redirect correctly"
The file test.txt contains
http://www.google.es

Answer 1

See this statement here,
$link = fread($myfile,filesize($link));
^^^^^^^^^^^^^^^
filesize() function expects the file path as it's argument, but you're passing an undefined variable $link.
So the above statement should be like this:
$link = fread($myfile,filesize($file));
Also, use exit(); after header(...); because header(...); itself is not sufficient to redirect the user to a different page.
header("Location: $link");
exit();

Answer 2

You're using the wrong variable for
filesize($link)
which should be $file
filesize($file)
(Edit):
Debugging procedure (and with error reporting set to catch and display).
Having commented out the header and echoing the $link variable
$file = "test.txt";
$myfile = fopen($file, "r") or die("Unable to open file!");
echo $link = fread($myfile,filesize($link));
fclose($myfile);
// header("Location: $link");
...you would have been presented with the following notice/warning:
Notice: Undefined variable: link in /path/to/file.php on line x
Warning: fread(): Length parameter must be greater than 0 in /path/to/file.php on line x
Since fread() couldn't figure out the filesize, it failed to to "read" it.
And of course as Rajdeep stated in his (much better) answer, to add exit; after header. Yours would have (most likely) worked, but it is indeed better practice.