What does mean --[[ in NodeJS? - node.js

I'm googling for a long time but there are no explanation of my problem. When I input in NodeJS interpreter --[[ then it does not allow me do something else. Is it a bug or it's a feature which I can use? How? Could someone explain me this? Thanks for advance.

The interpreter is waiting for you to close the two arrays you opened with [[ and will keep accepting input until you close both with ]], at which point it will correctly crash because you cannot subtract (--) from an array.

Related

Multithreading Problem - Not understanding how the concept of printf implemented in concurrency

Im struggling a problem in multithreading which I have two threads running over one printf ; and I don't know how exactly those four cases that's already explained in that video are correct?! could anyone please illustrate more about them? appreciated for any help to understand why what's explained here to that problem is correct !
I'm attaching down the video of the problem:
enter link description here
Appreciated for any help for how those 4 cases of the problem are correct .

S3 NodeJS -ListObjects always returns 0

The code for this question is already here:
Does writing to S3(aws-sdk nodeJS) conflict with listing objects in a bucket?
Please be sympathetic, I've been on this problem for days and I'm a complete rookie. I am trying to poll for a list of objects(haveFilesBeenWrittenToBucket method) and then read the file when there are objects (readFile method). If I place a breakpont on the callback(items) in the haveFilesBeenWrittenToBucket, everything works fine. If I don't, I always get 'number of items 0' written out to the console. It is not predictable exactly when the stuff will be written to S3, but it should be within a minute. There appears to be a race condition, and I would be very grateful if anyone could help me out here. I'm desperate for ideas. Thanks so much.
P.S. I was advised to make this a separate question to the one asked in the link.
In the end, I was barking up the wrong tree- my error had nothing to do with node.

Low Pass Filter in Verilog (De0 Nano)

I'm learning verilog and was wondering how to implement a low pass filter in an fpga,
I am looking for a cut off frequency of around 50Hz,
I don't know how/where to start,
Can anyone point me in the right direction to help me get started?
Thanks in advance
What have you tried so far?
This is a easily answered with google:
http://jason.sdsu.edu/~ashrafi/PDF/filters_FPGA.pdf
http://file.scirp.org/pdf/CS_2015021515483091.pdf

Is there a way to know how many volatile messages are dropped with Socket.IO on Node.js?

I searched a bit around and didn't find nothing about this particular issue. I am currently developing something that involves Socket.IO on Node.js.
My question is pretty simple : is there a way to know how many messages are dropped from a socket.volatile.emit() ?
Thanks for any tips!
https://github.com/LearnBoost/socket.io/blob/master/lib/transport.js#L524-534
No counter incremented, but you could turn on logging to take a look.

Controlling text-mode output in Linux | C / C++

First, I apologize for any sillinesses that might occur, as I'm not quite sure as how to properly put this question.
I recently got curious about how some applications (like Midnight Commander) control the text-mode output, forming so-called "Text-based user interface", idk. Is that some evil magic with standard output operations or something else that I'm unaware of? I did some poking around google, but didn't find anything of particular interest, and I hope someone here can point me on the right way.
Thanks in advance,
~Insomnia Array
What you're looking for is NCurses - a library which uses special terminal characters to set color, position, etc.
http://www.gnu.org/s/ncurses/
In addition to ncurses, take a look at S-lang.
http://www.s-lang.org/

Resources