Is it Kosher to ask the same question multiple times on different SO sites? This really applies to command line utility questions on SF and SU.
Last I checked, no. 99.9% of all questions really only belong on one site. While there is some overlap when you look at broader categories of questions (scripting for example) - the intent really does point you to one site or another. This has been discussed in greater detail elsewhere on meta. many times.
I will, for convenience, repeat my answer here that I gave elsewhere:
If it is clearly a question that does belong on another site, migrate it and then treat it as duplicate.
If it is a borderline question, let it live in both cultures, as the answeres will be different, programmers answering for programmers, and admins answering for admins.
Yes, it is important to keep the sites focused, but frankly, I am a programmer and will ask questions in SO mainly. So if I have a borderline question I will ask it in SO, not researching SF or SU upfront.
Linking the questions in a comment or the text will be of help and might point me to some additional answers. But I might not understand them, as the answerer expects too much from me as knowledge of the other community goes.
This view seems to be backed up here.