Small issues

Hello,
Great job this check worked great out of the box, I applied ruddockr suggestion to have CPU usage and not Idle time.
I noticed two small issues :

If you do not have any swap you get the divide by zero error noticed by helium_rday, as a quick fix I added a +1 in the division at line 290 and 291.

I always get a empty disk io, the perfdata are there but the output is always :
DISK OK io : |sda1_read=0.00;100;150 sda1_write=0.00;70;100 with nothing after the “io : “. I’m not a Perl expert but I noticed that the $return_str is initiliazed but no data is added to it.