Read it one record at a time:

open(INPUT,"filename.txt") or die "Will not open input: $!";
open(OUTPUT,">output.txt") or die "Will not open output: $!";

local $/ = \164;
while( <INPUT> ) { ## Updated per jwkrahn's post below
    print OUTPUT "$_\n";
}
close OUTPUT;
close INPUT;
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BTW: The semicolon after open(OUTPUT,">output.txt"); is kinda a givaway that you didn't have the error checking :)

As a one-liner:

perl -ple"BEGIN{$/=\164}" filename.txt >output.txt
[download]

Change  while( <IN> ) { to  while( <INPUT> ) { and it may work better.

Took a few seconds to run, thanks!
The superfluous semicolon ended up in the opening of the output file while I was changing the names of the files to protect the innocent.

That will certainly fail in many circumstances. See Ikegami's post and my example. If you are unlucky enough to break a wide character in half with 164 byte reads, well, that would suck

Yeah, don't forget that “memory” is virtual. In other words, it is a disk-file. So your program tried to copy 168 megabytes from one disk file to another, the hard way. It probably never succeeded in doing just-that.

There are several ways to do it (of course), but yes, the bottom line is that you need to read n bytes at a time and write each piece out followed by a newline.

use strict;

my $length = 164;

my $file = 'path/to/filename.txt';

open(my $F, '<:encoding' , $file) 
or die "cant open $file\n$!\n"; 

# you will supply the right value for 'encoding'.  
# one common example is 'utf8'

while( read( $F, my $record, $length ) ){
    # do something with $record
}
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my $c = 'some_scalar_data';

test_for_wide_chars: {
    
    require bytes;
    
    if ( bytes::length($c) > length($c) || 
           ($] >= 5.008 && $c =~ /[^\0-\xFF]/)) {   
         
        print "i found a wide character!"              

    }

    no bytes;

}
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If by "each record is 164 characters long", our friend Phil really meant that each record is 164 bytes long, than Browser's solution would be fine.

It was

Six hours of research to find a semantic quibble for a problem that was solved five hours ago?

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

Ah young Browser, wide characters are no laughing matter!

Have you ever done any web programming? If so then you'll have run into wide chracters when using HTML entities.

How about this, try this code and witness the power of wide characters, which really do exist!

use LWP::UserAgent;
open($F, '>:utf8' , 'wide-chars-example.html');
$url = 'http://www.w3schools.com/tags/ref_symbols.asp';
$html = LWP::UserAgent->new()->get($url)->content;
print $F $html;
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Now open the newly made file using your method... Try:

your_method: {
   local $/ = 2;
   #open 'wide-chars-example.html', process the 'records'
}
[download]

You'll get an interesting surprise!

Take care!