If I have a program that takes some input data, frobnicates the data, and outputs the result, should the name of the program be the verb, "frobincate", or the noun, "frobnicator"?
Here's a hypothetical invocation with the verb form:
cat data.txt | frobnicate > frobnicated.txt
and here is the same invocation with the noun form:
cat data.txt | frobnicator > frobnicated.txt
(Obviously, "frobnicate" is an imaginary verb used as an example here.)