First I'll try to answer the general question. Scroll down for my thoughts on the specific post.
If you know there is no reason at all for the downvotes, then the answer is to do nothing. Downvotes that are accidental or result from strange one-off misunderstandings of a post--that is, random downvotes--are more than made up for by upvotes in the long run. In terms of reputation points, upvotes outweigh downvotes even in the short run, because each upvote gives more rep than a downvote takes away, especially on answers.
The more interesting (and also more common) issue is what to do when a post is downvoted and you're not sure if there's a reason. I'll focus on answers here. These are the things I usually ask myself when I notice that an answer of mine has been downvoted and it's not immediately obvious why someone would have downvoted it:
Are there comments on your answer explaining the downvotes? Could a comment that seemed like it wasn't even a criticism actually have been intended as one? Just as it is sometimes hard to write a good question or answer, it can be hard to write a good comment, too.
Is there something wrong with your answer that is apparent by reading the question or the other answers, or maybe other posts that link to or from the post? Or that voters may think is apparent?
While I find this explains a lot of downvotes, it's also important not to take things too far and assume there must be a clue somewhere. Sometimes an accidental or pointless downvote is just that and nothing more.
Does the answer make claims that seem unusual, without explaining why they are true?
Does the answer make claims that seem vague, without explaining what they mean?
Are the downvotes coming in as part of what appears to be a concerted effort to abuse the system?
This isn't intended as an exhaustive list; it's just what I tend to think of, in the order I tend to think of them. And I'm a little reluctant to include #5, because it's different from the others: it's not obvious that I actually should be asking myself that question, except in unusual cases. Personal, spite-driven downvoting is probably rare, and when it happens the solution is either for the system to reverse it automatically or to inform a moderator in case there happens to be some action they can take. In contrast, 1-4 are all about the choices I have and the action I can choose to take.
Reasonable actions to take depending on the circumstances include editing, commenting, and posting on meta to get other people's views about the post and the situation, exactly as you have done here. Note that this is potentially useful precisely because the downvotes may not be random and pointless. And in this case, I don't think they were.
Your answer to "What is the point of sh being linked to dash?"
It seems to me that, even in its current state of revision, some combination of #3 and #4 apply.
As you say, you added quotes from an official source to your answer. That did improve your answer. But I don't think it's clear what exactly you are claiming, or how it could be supported by the quotes you used, when you say that you think
/bin/sh is linked to
/bin/dash for compatibility reasons. You correctly state that
#!/bin/sh is frequently used as a hashbang line for shell scripts, and then you say:
so by moving to
dash and not making a symbolic link, a lot of scripts would fail to run properly(or at all).
But that doesn't really make sense, because:
/bin/sh was already a symbolic link. The question is why it links to
dash. It used to link to
- What would it even mean to move to
dash without changing that symlink? The only thing I can think of is that you might be talking about expecting everybody to write
#!/bin/dash instead of
#!/bin/sh, and that you might be claiming that it is for "compatibility" that
/bin/sh even still exists. I really cannot tell.
In a very weak sense, almost everything anyone ever does while using a computer is for compatibility reasons. If I drag a file icon from one folder window to another, that's for compatibility with the traditional way file browsers expect me to transfer files. If I enter a password, that's for compatibility with the authentication system.
/bin/sh doesn't just exist for historical reasons. It is whatever "POSIX shell" the developers of a system intend for scripts to use, if those scripts' authors do not stipulate another shell.
Because "compatibility" can mean so many things, and because none of them seem to be supported by the quotes from official sources that you included in your post, it is not currently obvious what your post is actually saying, much less whether or not it is true. You don't have to edit your post further if you don't want to, but if you choose to do so, then I would encourage you to replace "for what I think is compatibility reasons" with something clear and specific, and then make sure that claim is fully and clearly supported by your sources.