$. and eof should help 
my $count=3;
 
while (<DATA>) {
  next if ($.-1) % $count and  ! eof;
 
  print @gulp;
  print "-----\n";
  @gulp=();
   
} continue {
  push @gulp,$_
}
__DATA__
a
b  
c 
d
e
f
g
h

[download]

I'm sure there are more elegant solutions...

Cheers Rolf

In reply to Re: reading several lines in a gulp by LanX
in thread reading several lines in a gulp by John M. Dlugosz

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