open (FH, "file.html");
my $find = quotemeta('here.company.com/pagedir'); 
## you can use quotemeta like this.  
my $replace = 'there.company.com'; 
## also it is better to define these outside of your loop
my $outstring;   
## this is a temp variable
while (<FH>) {  
	my $string = $_;
	$string =~ s/$find/$replace/g;
	$outstring .= $string;  
	## this concatenates $string to $outstring
}
close (FH);
open (FH, ">file.html");  
## > means open new file for writing
print FH $outstring;  
## a plain 'print' prints to STDOUT.  you want to print to 
## your filehandle instead.
close (FH);