my ($id) = ( $_ =~ /Logical device ID=(\w+)/ );

##</code><code>##

use Data::Dump;
dd  { line => $_, id => $id };

##</code><code>##

my $id;
while.... {

    $id  = $1 if /Logical device ID=(\w+)/ ;
    dd  { line => $_, id => $id };
}