Link: NASA DASHlink - Real System Failures
The Observed Failures slide deck from NASA DASHlink (via many places) is an interesting and even alarming collection of observed failures in hardware and software, mostly avionics related. I find it both entertaining and a useful reminder that all of this digital stuff is really analog underneath and that leads to interesting failure modes. Lest you think that all of these were hardware faults and us software people can be smug, well, not really. There are more; read the whole thing, as they say.
Why I think Emacs readline bindings work better than Vi ones
I recently saw a discussion about whether people used the Emacs bindings for readline editing or the Vi bindings (primarily in shells, although there are plenty of other places that use readline). The discussion made me realize that I actually had some opinions here, and that my view was that Emacs bindings are better.
(My personal background is that vim has been my primary editor for years now, but I use Emacs bindings in readline and can't imagine switching.)
The Emacs bindings for readline aren't better because Emacs bindings are better in general (I have no opinion on that for various reasons). Instead, they're better here because the nature of Emacs bindings make going back and forth between entering text and editing text, especially without errors. This is because Emacs bindings don't reuse normal characters. Vi gains a certain amount of its power and speed from reusing normal letters for editing commands (especially lower case letters, which are the easiest to type), while Emacs exiles all editing commands to special key sequences. Vi's choice is fine for large scale text editing, where you generally spend substantial blocks of time first entering text and then editing it, but it is not as great if you're constantly going back and forth over short periods of time, which is much more typical of how I do things in a single command line. The vi approach also opens you up to destructive errors if you forget that you're in editing mode. With Emacs bindings there is no such back and forth switching or confusion (well, mostly no such, as there are still times when plain letters are special or control and meta characters aren't).
Another way of putting this is that Emacs bindings at least feel like they're optimized for quickly making small edits, while vi ones feel more optimized for longer, larger-scale edits. Since typo-fixes and the like are most of what I do with command line editing, it falls into the 'small edits' camp where Emacs bindings shine.
Sidebar: Let's admit to the practical side too
Readline defaults to Emacs style bindings. If you only use a few
readline programs on a few systems, it's probably no big deal to
change the bindings (hopefully they all respect
But I'm a sysadmin, and I routinely use many systems (some of them
not configured at all) as many users (me,
root, and others).
Trying to change all of those readline configurations is simply not
feasible, plus some programs use alternate readline libraries that
may not have switchable bindings.
In this overall environment, sticking with the default Emacs bindings is far easier and thus I may be justifying to myself why it 'makes sense' to do so. I do think that Emacs bindings make quick edits easier, but to really be sure of that I'd have to switch a frequently used part of my environment to vi bindings for long enough to give it a fair shake, and I haven't ever tried that.
As a related issue, my impression is that using Emacs bindings have become the default in basically anything that offers command line editing, even if they're not using readline at all and have reimplemented it from scratch. This provides its own momentum for sticking with Emacs bindings, since you're going to run into them sooner or later no matter how you set your shell et al.