use strict; 
use warnings; 
my @entry; 
my $new_day; 
while (my $line = <DATA>) { 
    if ( $line =~ /^([1-9]|[12]\d|3[01])\s*$/ ) { 
        $new_day = $1; 
        next; 
    } 
    die 'internal error' if !$new_day; 
    $entry[$new_day] .= $line; 
} 
for my $day (1..4) { 
    print $day, "\n", $entry[$day], "\n"; 
} 
__DATA__ 
1  
blah, blah, blah  
over 2 lines   
 
2  
3   
 
2nd something or other starting at  
8 p.m.   
 
sometimes more than one line for the entry  
4