#usr/perl -w
use strict;

my $inPath = "somepath";
my $outPath= "outfile";
my $largefile = "large file";

open (INFILE, "<", $path2File) or 
    die "Can't open $path2File for read";

open (OUTFILE, ">", $outPath) or
     die "Can't open $outpath for write";
     
open (LARGE, ">",$largefile) or
     die "Can't open $largefile for write";
     #I don't see why this is necessay!
     
#do something here.... 
while (<INFILE>)
{  ....
   print OUTFILE "some_data\n";
}
     
#in general, open the files that you
#need to use at the beginning of the program and then
#use those file handles. 
#A "re-open" of a file handle for append is very 
#"expensive" thing within a loop in terms of performance.
#Don't do that.