Well, now at least I am getting a long list of 1's.

Here is what I am using.

use warnings;
use strict;
use autodie;

open IN, "<D:\\baseline_pattern.txt";
binmode IN;
my @content = <IN>;
close IN;

foreach my $num (qw/0 1/) {
    my @count = ("@content" =~ /$num+/sg);
    open my $fh, ">iterations$num.txt";
    print "$_\n" for @count;
    close $fh;
}
[download]

There are files "D:\iterations_1.txt" and "D:\iterations_0.txt" that I created.

However there was nothing written to these files.

Should there be a sprintf?

Nope, print is, or should be doing the job - looks like there might've been 2 mistakes -, try print $fh "$_\n" for @count;
A user level that continues to overstate my experience :-))

Well something is working right because I got no errors.

However, nothing was written to either file.

This is the code now.

use warnings;
use strict;
use autodie;

open IN, "<D:\\baseline_pattern.txt";
binmode IN;
my @content = <IN>;
close IN;

foreach my $num (qw/0 1/) {
    my @count = ("@content" =~ /$num+/sg);
    open my $fh, ">iterations_$num.txt";
    print $fh "$_\n" for @count;
    close $fh;
}
[download]

Should the '>' in front of iterations be a '>>' for appending?

How can I fully qualify where the files are that data should be written?

I can barely make sense of what is going on in this script