-e  File exists.
-z  File has zero size (is empty).
-s  File has nonzero size (returns size in bytes).

>perl -we "use strict; my $file = 'c:\scripts\vacuum.txt'; if (-e -s $file){print qq(it exists and has not zero lenght\n)} else {print qq(exists but zero lenght\n)}"
exists but zero lenght

>perl -we "use strict; my $file = 'c:\scripts\002.txt'; if (-e -s $file){print qq(it exists and has not z
ero lenght\n)} else {print qq(exists but zero lenght\n)}"
it exists and has not zero lenght