use strict;
use warnings;

local $/="\narray ";
while (<DATA>){
	s/\n(?!unassigned)(:?array)?/ /g;
	print  my $row=(m/^array/?"":"array "). "$_\n";
}
__DATA__
array A
physicaldrive 2C:1:1 port 2C:box 1:bay 1 SAS 1 TB OK
physicaldrive 2C:1:2 port 2C:box 1:bay 2 SAS 1 TB OK
array B
... etc ...
unassigned
physicaldrive 7C:3:7 port 7C:box 3:bay 7 SAS 1 TB OK
...

##</code><code>##

array A physicaldrive 2C:1:1 port 2C:box 1:bay 1 SAS 1 TB OK physicaldrive 2C:1:2 port 2C:box 1:bay 2 SAS 1 TB OK  
array B physicaldrive 2C:1:3 port 2C:box 1:bay 3 SAS 1 TB OK physicaldrive 2C:1:4 port 2C:box 1:bay 4 SAS 1 TB OK  
... 
array J physicaldrive 6C:3:3 port 6C:box 3:bay 3 SAS 1 TB OK physicaldrive 6C:3:4 port 6C:box 3:bay 4 SAS 1 TB OK  
array K physicaldrive 7C:3:5 port 7C:box 3:bay 5 SAS 1 TB OK physicaldrive 7C:3:6 port 7C:box 3:bay 6 SAS 1 TB OK
unassigned physicaldrive 7C:3:7 port 7C:box 3:bay 7 SAS 1 TB OK physicaldrive 7C:3:8 port 7C:box 3:bay 8 SAS 1 TB OK