#!/usr/bin/perl
use strict;

my @array;
#open(my $fh, "<", "../temp/out2.asc")
#    or die "Failed to open file: $!\n";
my $fh=\*DATA; 

while(<$fh>) {
  if (/^START/../^END/){
    chomp;
    push @array, $_;
    } 
  else{ 
   if (scalar(@array)) {
     print join " ", @array;
     print "\n";
     @array=(); 
     } 
   }
}

   if (scalar(@array)) {
     print join " ", @array;
     print "\n";
     @array=(); 
     } 
close $fh;

__DATA__
START
TIME: 3
ALT: 3.1
TEMP: 4.3
END

START
TIME: 2.6
ALT: 8
TEMP: 1
END

START
TIME: 6.1
ALT: 7.2
COLOR: 43

STRENGTH: 7

TEMP: 9.3
END