Maybe this helps?

use strict;

while(<DATA>){
$_ =~s /\s+/:/ig;
my ($a, $b, $c, $d, $e, $f) = split /:/;
my $A = int scalar $a;    #marker
my $B = int scalar $b;    #data
my $C = int scalar $c;    #data
my $D = int scalar $d;    #marker
my $E = int scalar $e;    #$data
my $F = int scalar $f;    #$data

print "SCALAR: $a-> $b, $d-> $e\n";
print "INT PART: $A-> $B, $D-> $E\n";

# print FH "$B\n$E\n"; # your FH
}


__DATA__
50545  4.393864E+00  .0   50546  9.589456E+00  .0
50547  2.690474E+00  .0   50548 -1.668896E+01  .0
50549 -3.391918E+01  .0   50550 -3.634581E+01  .0
50551 -3.176630E+01  .0   50552 -1.747830E+01  .0
50553 -5.256684E-01  .0   50554  1.135265E+01  .0
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