It's often a stupid rule. If you have a process that is stuck, you type "kill " to kill it. But kill doesn't tell you if the process was killed or not, so you have to double-check with "ps " to see if it is still alive. If it is, you try again with "kill -9 ". I suspect the reason is that for most signals, kill can't determine if the signal was acted upon or not. But for KILL and TERM it could wait a few milliseconds…
If you want that behaviour it is trivial to write a wrapper script that does this. If you don't want that behaviour, getting rid of it if it were built-in would be more difficult.
Note that the "rule of silence" (combined with the habit of writing documentation like longform essays) is also one factor that makes unix-like systems newbie-unfriendly. (Famous example: trying to exit vi) I think the rule makes sense within the specific constraints *nix programs are usually expected to work in (two output channels with no structure except the one informally defined by the program and the convention…
> Famous example: trying to exit vi To be fair, this has been fixed a long time ago. At least Vim (which is the Vi installed on most systems) shows the following message on startup: ~ VIM - Vi IMproved ~ ~ version 7.4.1829 ~ by Bram Moolenaar et al. ~ [...] ~ Vim is open source and freely distributable ~ ~ Help poor children in Uganda! ~ type :help iccf for information ~ ~ type :q to exit ~ type :help or for on-line…
Someone unfamiliar might just be dumped into vi because some other program thought it'd be great to open a text editor, e.g. for a commit message. You're unlikely to run vi intentionally unless you also know you want to run vi and how to exit, I guess.
Note that I'm not arguing for structured binary data. Structured text (e.g. s-expressions, JSON, even the-extensible-structured-text-format-which-shall-not-be-named) can last just as long. Indeed, S-expressions have existed since the 1950s. There's no particular reason why /etc/passwd couldn't be: ((root nil 0 0 root /root /bin/bash) (daemon nil 1 1 daemon /usr/sbin /usr/sbin/nologin) …) There are any number of simil…
But column-oriented output is still structured and tools like AWK are meant to be a "programmable filter" on it. Reading or outputting deeply nested structures like JSON or S-exps would make it less practical to pipe programs together and instead have big "monolithic filters" with lots of options.
That just illustrates the limitations of the pipe abstraction, as something only able to send sequentially-read unstructured data.
It's often a stupid rule. If you have a process that is stuck, you type "kill " to kill it. But kill doesn't tell you if the process was killed or not, so you have to double-check with "ps " to see if it is still alive. If it is, you try again with "kill -9 ". I suspect the reason is that for most signals, kill can't determine if the signal was acted upon or not. But for KILL and TERM it could wait a few milliseconds…
kill sends a signal, that's all it does. It doesn't care about what the process did with it.
It's often a stupid rule. If you have a process that is stuck, you type "kill " to kill it. But kill doesn't tell you if the process was killed or not, so you have to double-check with "ps " to see if it is still alive. If it is, you try again with "kill -9 ". I suspect the reason is that for most signals, kill can't determine if the signal was acted upon or not. But for KILL and TERM it could wait a few milliseconds…
It is easy to work around this issue if it bothers you (wrapper script / display exit status in PS1). That's the whole point - it is easy to make applications talk if they are quiet by default, but it is much more difficult to make them be quiet and only talk when necessary if they are noisy by default.
It's often a stupid rule. If you have a process that is stuck, you type "kill " to kill it. But kill doesn't tell you if the process was killed or not, so you have to double-check with "ps " to see if it is still alive. If it is, you try again with "kill -9 ". I suspect the reason is that for most signals, kill can't determine if the signal was acted upon or not. But for KILL and TERM it could wait a few milliseconds…
It's often a stupid rule. If you have a process that is stuck, you type "kill " to kill it. But kill doesn't tell you if the process was killed or not, so you have to double-check with "ps " to see if it is still alive. If it is, you try again with "kill -9 ". I suspect the reason is that for most signals, kill can't determine if the signal was acted upon or not. But for KILL and TERM it could wait a few milliseconds…
It's often a stupid rule. If you have a process that is stuck, you type "kill " to kill it. But kill doesn't tell you if the process was killed or not, so you have to double-check with "ps " to see if it is still alive. If it is, you try again with "kill -9 ". I suspect the reason is that for most signals, kill can't determine if the signal was acted upon or not. But for KILL and TERM it could wait a few milliseconds…