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SEARCH KEYWORD -- Command line arguments

  What are some lesser known but useful Unix commands?

A few that come to mind, some less known, some more: xargs or parallel: run things in parallel, with lots of options sed and awk: more well-known but still super useful for processing text files, and faster than Python or Ruby m4: simple macro processor screen: powerful terminal multiplexing and session persistence yes: print a string a lot cal: nice calendar env: run a command (useful in scripts) look: find English words (or lines in a file) beginning with a string cut and paste and join: data...

   Linux,Unix,Command,Less used     2011-12-27 09:27:49

  Why is single threaded Redis so fast

Redis is a high-performance, in-memory key-value database. According to official test reports, it can support around 100,000 QPS (queries per second) on a single machine. However, Redis uses a single-threaded architecture in its design. Why does Redis still have such high performance with a single-threaded design? Wouldn't it be better to use multiple threads for concurrent request processing? In this article, let's explore why Redis has a single-threaded architecture and still maintains its spe...

   REDIS,SINGLE-THREADED,MULTI-THREADING     2023-02-28 05:16:22

  Python internals: how callables work

[The Python version described in this article is 3.x, more specifically - the 3.3 alpha release of CPython.] The concept of a callable is fundamental in Python. When thinking about what can be "called", the immediately obvious answer is functions. Whether it’s user defined functions (written by you), or builtin functions (most probably implemented in C inside the CPython interpreter), functions were meant to be called, right? Well, there are also methods, but they’re not very ...

   Python,Callable work,Rationale     2012-03-24 05:20:27

  How to install Oracle database on Linux using response file

There are two ways to install Oracle database on Linux :1). Using GUI; 2). Using response file. In this post, the method for using response file will be introduced. To install Oracle, please first get the Oracle database installation file ready. It can be downloaded from Oracle OTN. You need to have an Oracle account before you can download them. And there are three major components of the Oracle database installation : 1). The installation itself; 2). The network configuration; 3). Database cre...

   LINUX,HOW TO,ORACLE DATABASE     2017-06-03 04:15:49

  HeartBleed: OpenBSD now starts to clean up OpenSSL

Since the disclosure of HeartBleed bug in OpenSSL, some arguments emerge around the safety of OpenSSL, the largest open source SSL/TLS library used by large number of servers, applications. Some people are even starting to create their own version of SSL library. This includes OpenBSD, a famous Unix like open source operating system. Just a few days after the HeartBleed bug, OpenBSD forked a new branch of OpenSSL and started to clean up the forked branch and plans to merge it to its own cod...

   HeartBleed,OpenBSD     2014-04-15 04:21:26

  JavaScript-style object literals in PHP

The object literal notation in JavaScript looks like: var fido = {name: "Fido", barks: true}; or var fido = {}; fido.name = "Fido"; fido.barks = true; From assoc arrays to objects In PHP you would call that an associative array. $fido = array( 'name' => "Fido", 'barks' => true ); And you can easily make it an object too: $fido = (object)$fido; echo gettype($fido); // "object" Or if you want to start with a blank object and add stuff to it: $fido = (object)array(); or $fido...

   PHP,JavaScript,Object,Function call,Self vs this     2011-11-30 11:11:45

  JavaScript's Two Zeros

JavaScript has two zeros: -0 and +0. This post explains why that is and where it matters in practice. The signed zero Numbers always need to be encoded to be stored digitally. Why do some encodings have two zeros? As an example, let’s look at encoding integers as 4-digit binary numbers, via the sign-and-magnitude method. There, one uses one bit for the sign (0 if positive, 1 if negative) and the remaining bits for the magnitude (absolute value). Therefore, -2 and +2 are encoded as f...

   JavaScript,zeros     2012-03-24 05:21:49

  How does GoLang know how many CPUs to use?

When running lscpu command on Linux, it will list the CPU info on the machine. Take one example where there is one CPU with 2 cores and each core has two threads which indicates there are 4 cores available. Now let's see how many cores GoLang program would identify. From output, NumCPU and GOMAXPROCS both output 4 which is expected. How does go runtime get this info, does it get it through similar command like lscpu or /proc/cpuinfo? Let's dig more in GoLang's source code. In runtim...

   GOLANG,CPU,NCPU     2020-12-29 23:22:15

  Understanding PHP's internal function definitions

Welcome to the second part of the “PHP’s Source Code For PHP Developers” series. In the previous part ircmaxell explained where you can find the PHP source code and how it is basically structured and also gave a small introduction to C (as that’s the language PHP is written in). If you missed that post, you probably should read it before starting with this one. What we’ll cover in this article is locating the definitions of internal functions in t...

   PHP,internal function,definition,rationale     2012-03-16 10:46:26

  How DNS lookup works

When accessing a website, a domain name would be needed normally. To get to the actual web server, the domain name must be mapped to an actual IP address and the IP address will be used to reach the web server. The process of finding the IP address from a domain name is called DNS lookup.  How does DNS lookup work? There are tons of domain name and IP address around the world, there must be some well-designed architecture to support fast lookup. This post will explain how this works. DNS Se...

   DNS,DNS LOOKUP     2022-09-09 23:11:03

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