Should flags in POSIX-style operating systems be prefixed by “no” or “no_”?

Question

When you have a boolean option and a flag for setting it to false by prefixing "no" to the name, should it be "no" or "no_"? What's most commonly used or better style? For example:

--no_foo

or

--nofoo

Answer 1

Neither. Use no- i.e. --no-foo.