I have no idea what you are doing wrong but this works.

#!/usr/local/bin/perl -w
use strict;

my ($str);

$_="what\n is going\non here?\n";

print "Before $_\n";

s/\n//g;

print "After $_\n";

It prints out the following:

Before what 
is going 
on here?

After what is goingon here?

There is no problem. Double check your code. :)

metadoktor

"The doktor is in."