Thanks for your reply and help but how can I modify my existing program? The reason being is that the ending program won't be as a simple as I have it. There will be numerous changes throughout.

Again thanks :-)

erikharrison is dead on. In order for your existing program to work, you really have to open a temp file, write to it, then clob the first file by moving the temp file over the first file:

use strict;
use IO::File;

my $in  = IO::File->new;
my $out = IO::File->new;
my $change_on  = "FChangeBar Yes";
my $change_off = "FchangeBar No";  # hmmm, lower case c?


$in->open('test.mif') or die "can't read input";
$out->open('>tmp.mif') or die "can't write output";

while (<$in>) {
   s/$change_on/$change_off/g;
   print $out $_;
}

$in->close or die "can't close input";
$out->close or die "can't close output";

rename('tmp.mif','test.mif') or die "can't rename";
[download]

Here is a much cooler version that uses Tie::File:

use strict;
use Tie::File;

my @file;

tie @file, 'Tie::File', 'test.mif' or die "cannot tie file";

s/(FchangeBar )Yes/$1No/g for @file;
[download]

But, you might not be able to incorporate this into your ending program. At any rate, you are welcome and good luck! :)

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)