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
}