How can I read multiple lines of a file into blocks in Perl?

Question

I have a file which contains the text below.

#L_ENTRY    
#LEX        
#ROOT       
#POS        
#SUBCAT     

        

Answer 1

If you set the input record separator variable to the empty string, then perl will work in paragraph mode, and return a block at a time separated by one or more blank lines in the input data

use strict;
use warnings 'all';

local $/ = '';


my $n;
while (  ) {
    printf "Block %d:\n<<%s>>\n\n", ++$n, $_;
}

__DATA__
A
B
C
D
E
F

A
B
C
D
E
F

output

Block 1:
<>

Block 2:
<>