Also,  /.*rrd$/ will match both of the strings  "rrd" and  "rrd\n" so perhaps you should use  /.*rrd\z/ instead.

Or perhaps even:  'rrd' eq substr( $_, -3 )

It would be pretty unusual to have a file name that ends with \n, so I see that as an edge case that's probably not worth worrying about.

It's probably better to have a check after the call to RRDs::info, so I've inserted:

    my $info = RRDs::info "$logsdir/$rrd";
    # Check to ensure we actually have a valid rrd file
    unless ($info->{filename}) {
        print qq|"$logsdir/$rrd" doesn't appear to be a valid rrd log,
+ skipping\n|;
        next;
    }
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Which does the trick...

$ touch foo.rrd

$ ./rrd-resize.pl 
Starting, found 1 rrd files


Processing foo.rrd
"./foo.rrd" doesn't appear to be a valid rrd log, skipping
Finished, processed 1 files in 0.00 seconds
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