use strict;
use warnings;
my %devices;
$_ = q|device1 is 2.3.5.1 . . . 56% /var 38% / 31% Interleaved device1 Tue Sep 9 11:26:44 ist 2005 logging to device2 is 2.3.5.1 . . . 56% /var 44% / 31%|;

my @arr = /(device\d+)\sis\s.+?\/var\s+(\d+%)/g;
%devices = @arr;

open(XLS, ">/path/to/file.xls") or die "Could not open file: " . $!;

foreach my $device (sort keys (%devices)) {
    print XLS $device . "\t" . $devices{$device} . "\n";
}

close XLS;