coolaj86

Getting Started with NPM (as a developer)

As easy as 1, 2, 3!

Updated:

• Aug, 08, 2022 update config docs for npm 8+
• Jul 27, 2021 add private scopes
• Jul 22, 2021 add dist tags
• Jun 20, 2021 update for --access=public
• Sep 07, 2020 update docs for npm version

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

klange

Since this is on Hacker News and reddit...

• No, I don't distribute my résumé like this. A friend of mine made a joke about me being the kind of person who would do this, so I did (the link on that page was added later). My actual résumé is a good bit crazier.
• I apologize for the use of _t in my types. I spend a lot of time at a level where I can do that; "reserved for system libraries? I am the system libraries".
• Since people kept complaining, I've fixed the assignments of string literals to non-const char *s.
• My use of type * name, however, is entirely intentional.
• If you're using an older compiler, you might have trouble with the anonymous unions and the designated initializers - I think gcc 4.4 requires some extra braces to get them working together. Anything reasonably recent should work fine. Clang and gcc (newer than 4.4, at le

nikic

Why objects (usually) use less memory than arrays in PHP

This is just a small post in response to [this tweet][tweet] by Julien Pauli (who by the way is the release manager for PHP 5.5). In the tweet he claims that objects use more memory than arrays in PHP. Even though it can be like that, it's not true in most cases. (Note: This only applies to PHP 5.4 or newer.)

The reason why it's easy to assume that objects are larger than arrays is because objects can be seen as an array of properties and a bit of additional information (like the class it belongs to). And as array + additional info > array it obviously follows that objects are larger. The thing is that in most cases PHP can optimize the array part of it away. So how does that work?

The key here is that objects usually have a predefined set of keys, whereas arrays don't:

johanneswuerbach

---
language: objective-c
before_script:
- ./scripts/travis/add-key.sh
after_script:
- ./scripts/travis/remove-key.sh
after_success:
- ./scripts/travis/testflight.sh
env:
  global:

tsiege

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!






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mikehaertl

Docker Development Workflow

These ideas are WORK IN PROGRESS!

Summary

The core idea with this workflow is that we end up with a self contained docker image of your application. This image will not only contain our code, but also all the dependencies that are neccessary to run the code. This image can then be used for both, easy deployment in production and as basis for ongoing development.

The image is not a static, though. In fact, it will see many revisions over time - which is supported nicely through dockers inheritance approach. We basically

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

techgaun

Script

#!/bin/bash

yum install ncurses-devel openssl-devel -y
yum groupinstall "Development Tools" -y

cd /tmp
wget "http://erlang.org/download/otp_src_21.3.tar.gz" -O otp21.tar.gz

senderle

So you want to modify the text of a PDF by hand...

If you, like me, resent every dollar spent on commercial PDF tools, you might want to know how to change the text content of a PDF without having to pay for Adobe Acrobat or another PDF tool. I didn't see an obvious open-source tool that lets you dig into PDF internals, but I did discover a few useful facts about how PDFs are structured that I think may prove useful to others (or myself) in the future. They are recorded here. They are surely not universally applicable --
the PDF standard is truly Byzantine -- but they worked for my case.