Trim not removing end newline characters?

Question

This should be fairly straightforward. Say I have the following code:

$output = file_get_contents($random_name . ".txt");
echo "<pre>";
echo str_replace("\n", "\nN ", $output);
echo "</pre>";

And $output looks like this:

PDF Test File
N Congratulations, your computer is equipped with a PDF (Portable Document Format)
N reader! You should be able to view any of the PDF documents and forms available on
N our site. PDF forms are indicated by these icons:
N or.
N 
N 

And let's say I want to get rid of those two last newline characters, through the following:

$outputTrimmed = trim($output, "\n");

I would assume, that would output:

PDF Test File
N Congratulations, your computer is equipped with a PDF (Portable Document Format)
N reader! You should be able to view any of the PDF documents and forms available on
N our site. PDF forms are indicated by these icons:
N or.

But instead, this code:

$output = file_get_contents($random_name . ".txt");
$outputTrimmed = trim($output, "\n");
echo "<pre>";
echo str_replace("\n", "\nN ", $outputTrimmed);
echo "</pre>";

Results in:

PDF Test File
N Congratulations, your computer is equipped with a PDF (Portable Document Format)
N reader! You should be able to view any of the PDF documents and forms available on
N our site. PDF forms are indicated by these icons:
N or.
N 
N 

What am I doing wrong? It's probably something really, really simple... so I apologize.

Answer 1

You are probably using Windows End-of-line style.

Which is \r\n, not just \n.

Try replacing both.

OR, don't specify any charlist (2nd parameter). By specifying \n you are saying ONLY trim \n

trim($output)

See the docs here: http://www.w3schools.com/php/func_string_trim.asp#gsc.tab=0

---

EDIT (from your comments):

If trim() is not working try changing your string to a byte array and examining exactly what character is at the end of your string. This is making me suspect there's some other non-printable character interfering.

$byteArray = unpack('C*', $output);
var_dump($byteArray);

http://www.asciitable.com/