Shell pipes and in-place insanity
fakedrake.github.io
Shell pipes and in-place insanity
1–10 of 16 posts
Re: Shell pipes and in-place insanity
#2There's not really a STDIN or STDOUT.
The vision is a souped-up 64-bit modern C64.
Linux wants to be a mainframe.
Re: Shell pipes and in-place insanity
#3That was a contrived example.
The shell sets up the pipe and file redirections for each process in the pipeline, then lets them go. It has no control over when the child processes read or write. It could be a race condition, but it's written in such a way that it appears that the file will get truncated before it can be read virtually 100% of the time.
Re: Shell pipes and in-place insanity
#4NB: If you're going to use CSS styling for code examples, choose foreground and background colors, as well as text sizes, which are actually legible.
Monospace fonts, black on white, at default sizes, are your best bets.
Re: Shell pipes and in-place insanity
#5I think this behaviour is supposed to be a feature of shell. Pipelines are executed in parallel.
Also, see `sponge` from `moreutils` (http://kitenet.net/~joey/code/moreutils/):
$ man sponge
...
sponge reads standard input and writes it out to the specified file.
Un‐like a shell redirect, sponge soaks up all its input before opening the output file.
This allows constructing pipelines that read from and write to the same file.Re: Shell pipes and in-place insanity
#6This is the expected behavior of pipes[0]. A quick look at Lists [1] clears up how you can control this a little better (+Job Control). jamesdutc also linked to sponge, which may suit your usecase as well.
[0] https://www.gnu.org/software/bash/manual/bashref.html#Pipelines
[1] https://www.gnu.org/software/bash/manual/bashref.html#ListsRe: Shell pipes and in-place insanity
#7That was a contrived example. The shell sets up the pipe and file redirections for each process in the pipeline, then lets them go. It has no control over when the child processes read or write. It could be a race condition, but it's written in such a way that it appears that the file will get truncated before it can be read virtually 100% of the time.
You are right I should have clarify that. thank you
Re: Shell pipes and in-place insanity
#8NB: If you're going to use CSS styling for code examples, choose foreground and background colors, as well as text sizes, which are actually legible. Monospace fonts, black on white, at default sizes, are your best bets.
Counteranecdatum for the author: I find your choice of foreground and background colors, syntax highlighting colors, font style and size, and line length inside your code blocks to be quite legible and pleasant to read.
Please make these sorts of choices again in the future!
Re: Shell pipes and in-place insanity
#9NB: If you're going to use CSS styling for code examples, choose foreground and background colors, as well as text sizes, which are actually legible. Monospace fonts, black on white, at default sizes, are your best bets.
Um... I see almost-black Courier New on off-white, at 13px and a slightly increased line-height. That seems fine to me.
Re: Shell pipes and in-place insanity
#10NB: If you're going to use CSS styling for code examples, choose foreground and background colors, as well as text sizes, which are actually legible. Monospace fonts, black on white, at default sizes, are your best bets.
Um... I see almost-black Courier New on off-white, at 13px and a slightly increased line-height. That seems fine to me.
The body text is approximately legible size, but low contrast.
The code examples are all but unreadable.
http://i.imgur.com/ogS9yat.png
Here's a quick improvement for legibility. I'm not claiming a thing of beauty.
http://i.imgur.com/mW880fB.png
My general style guidelines are included here: