open my $READFILE, '<', $infile or die "Can not open $infile for parsing: $!" ;


##</code><code>##

open my $WRITEFILE, '>', $outfile or die "Can not open new replacement file: $outfile. $!";


##</code><code>##

while (<$READFILE>) {
     # do something to $_
     print $WRITEFILE $_ ;
}