There is room for other interpretations, but I'd say if it's super common for people to not know something, which appears to describe this, it doesn't meet the definition of basic.
I'd say "basic" shell knowledge is that commands or programs produce output which is where many stop and why it's common to use cat this way.
In general I tend to err less on the side of "you're holding it wrong" gatekeeping in tech and when there's a common issue with something, blame the tech rather than the users. Maybe the way shell handles input, output, and redirection isn't intuitive and poorly designed. For those that already know there's an ego thing going on condescending to users who haven't learned as much that prevent honest or productive conversations on these topics.
> In general I tend to err less on the side of "you're holding it wrong" gatekeeping in tech
That's not gatekeeping. I'm pretty sure anyone that points out `<` would like anyone that doesn't know it to become familiar with it. That's precisely why they mention it. To gatekeep would be for someone to say that people that aren't familiar with it shouldn't have access to the shell. No one is saying that.
> There is room for other interpretations, but I'd say if it's super common for people to not know something, which appears to describe this, it doesn't meet the definition of basic. I'd say "basic" shell knowledge is that commands or programs produce output which is where many stop and why it's common to use cat this way.
I feel that's the same bar as saying that knowing how to use a keyboard and mouse is not basic because most people just learn to use their phone's touch interface, given how there's now a lot of people that have a smartphone but not a computer. I don't mean in our circles, but in general.
What's probably going on is that the boundary between basic and intermediate probably moves depending on increased adoption with different proportions of motivations. That is, most learners of the shell before were probably motivated to use it as their main interface, later one of their main interfaces, and now maybe there's a lot of people that need to run a command or 2 but don't really want to use it as an interface at all, so they never bother to learn beyond the most absolute minimum they need to.
> Maybe the way shell handles input, output, and redirection isn't intuitive and poorly designed.
I don't think being intuitive is always the most important criteria to something being well designed. Many things imply trade-offs, and for example if the average potential user values versatility over intuitiveness, and there's a tradeoff to be made between the 2, it's ok to not go for the intuitive option.
That said, the redirection operators seem as intuitive as they can be. Arrow from file to command for input, arrow from command to file for output. What's a better alternative? To just remove file redirection features and leave piping?
Processes will have inheritable file descriptors. Right now, the easiest and quickest way to make ad-hoc arbitrary arrangements of file descriptors is with the shell's file redirection features. Doing it on anything else (Python, C, whatever) requires more code. That seems like successful design to me.
I'm not that person, so I don't know how they meant themselves to be interpreted. I interpret their comment as correcting the fact that file redirection is not a trick but a basic/core feature and emphasize that with their hyperbole of everyone knowing it from day one. I don't think they mean to dissuade people from using the shell. I don't think they mean their statement in the way of "if you didn't know this, you're not a real terminal user. Get out of here". Maybe I'm wrong and that was their motivation. I don't know.
I was also interpreting user3939382's use of gatekeeping in the context of other similar comments not just the one they were directly replying to. That's probably my mistake.
> Honestly I don't think that in 15+ years I ever saw that in the wild in any shell script
I've done it in shell scripts, very rarely interactively. In scripts, it sometimes just looks better defining that part first.
Wait until you see the redirect in the middle of program arguments. That's where it gets confusing. At least the redirect at the very beginning or very end of the line is easy. :)
"from day one", there's a lot of more important stuff to learn on day 1 than one "weird trick" that literally has no tangible benefits other than nerd sniping
I have more important things to worry about than making the line less readable and less maintainable
I have been aware of this feature for 20 year. I have also 20 years of muscle memory that makes me type the redundant cat. If you are used to it, it is hard to avoid and the benefit as minuscule. Also sometimes it makes it easer to extend the pipeline
> Briefly, here's the collected wisdom on using cat:
> The purpose of cat is to concatenate (or "catenate") files. If it's only one file, concatenating it with nothing at all is a waste of time, and costs you a process. The fact that the same thread ("but but but, I think it's cleaner / nicer / not that much of a waste / my privelege to waste processes!") springs up virtually every time the Award is posted is also Ancient Usenet Tradition.
And if you're in a situation where you care about the overhead of extra processes, you wouldn't be exploratively and iteratively constructing a query on the command-line - you'd have already done the exploration in order to understand exactly what query you needed, and then would be converting the query into a non-bash programming language for optimization.
Catenating a file with the output stream is quite useful in many circumstances. Paged data isn't always wanted, and it's not generally known if filters are needed before the file is seen. Cat is the standard way to print to stdout.
I'd say "basic" shell knowledge is that commands or programs produce output which is where many stop and why it's common to use cat this way.
In general I tend to err less on the side of "you're holding it wrong" gatekeeping in tech and when there's a common issue with something, blame the tech rather than the users. Maybe the way shell handles input, output, and redirection isn't intuitive and poorly designed. For those that already know there's an ego thing going on condescending to users who haven't learned as much that prevent honest or productive conversations on these topics.