how-to read huge file in perl

sub ReadHugeFileSpareResources 

{

open(MYINPUTFILE, "<filename.out");

while(<MYINPUTFILE>)

{

# Good practice to store $_ value because

# subsequent operations may change it.

my ($line) = $_;

# Good practice to always strip the trailing

# newline from the line.

chomp ($line);

# Action !!! Convert the line to upper case.

$line =~ tr/[a-z]/[A-Z]/;

# Print the line to the screen and add a newline

print "$line\n";

} #eof sub ReadHugeFileSpareResources