sub read_line {
    my $h = shift;
    local $/ = "\n"; 
    return <$h>
}

sub read_para {
    my $h = shift;
    local $/ = "";
    return <$h>;
}

use Fatal qw(open);
open H, '<', 'files.csv';
while (my $txt = read_file(*H)) {
      # process the CSV line and make the filename available in $fn
      open TXT, '<', $fn;
      my @paragraphs = read_para(*TXT);
      # process
}