Not outputting anything causes kill (on my system at least) to exit non 0
Not outputting anything isn't an option, for the case where -o pid is used in addition to other fields. The field number and order must be respected.
It's probably best to use some OOB indicator. How about NA, which I already use for non-numeric fields? it makes kill correctly choke. Would it be better to use NA in all the numeric fields, too? -- Laurent
