A few of us were talking about this the other day in chat, as we are now quite a bit larger and with several thousand Q&As, there are certain questions that are asked very often. Things like redirecting output, process substitution, batch renaming of files, fixing/reinstalling grub, etc.
Let's compile a list of the best/most complete answers to such common questions here, and then we can always close new questions as duplicates of those. That way, we can have a single, canonical answer to these things which we can edit and make as good as we can and avoid having the dupes pointing at each other all over the place. The inspiration comes from this meta AU question:
Ideally, I would like to see an answer below that collects as many as possible. I will make a start but please edit to add more. As part of this initiative, we should also consider asking such questions and answering them ourselves. For example, I just read this question over on SU, having that kind of thing here seems like a very good idea (not specifically for hardware, although that would be useful, but that type of canonical question*).
So, the idea would be to hash it out here, and once we have a decent list, make a meta Q&A like the ones above, listing them. Then, we make sure to close as dupes of the canonical.
Please vote for the answers below, upvote them if you consider the suggested Q&A to be a good candidate for the canonical one and downvote them if you don't. Upvoting the question itself is nice but less useful.
* I made a start here: How can I replace a string in a file(s)?