That depends on whether by numeric you mean a simple integer like 12 or a number like -12.15 or even 12E25. You might check that with a regex, similar to what kyle already posted

chomp($processor); # removes \n 

# would check for whole numbers like 1, 12, 389
if (! $processor || $processor !~ /^\d+$/){

#would check for numbers with optional decimal point and + or minus si
+gn
if (! $processor || $processor !~ /^(+|-)?\d+(\.\d*)?$/){
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There is a cpan module that has all kinds of regexes predefined (don't rememer the name atm), if you want to check for more complex numbers, that module would be a good idea

UPDATE: Note that in the example code you posted above you have a pointer to the result in $processor and not the result itself. If you just want the result of the ccc.ksh execution in $processor, better remove the \ in front of the left paren