Ammar Faizi ammarfaizi2

Prepare Your Linux Server

What Does This Really Do?

Basically we set up the timezone and locale, and only allow for SSH root login without password, by using SSH authentication key. We also add a basic Vim conviguration inside .vimrc by adding line numbers by default.

Then we update the repository and the system, and also add basic tools like nano, curl, tmux, even vim itself doesn't included by the system. zsh and git is prequisites for oh-my-zsh,

Understanding the Memory Layout of Linux Executables

Required tools for playing around with memory:

hexdump
objdump
readelf
xxd
gcore

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:

About

This is a local copy of the commands from:

This guide serves as a reference of collected information necessary for strict management of PGP keys. This includes keeping a master key that always remains

	#!/bin/bash
	#------------------------------------------------
	# Setup Ubuntu 16.04 with xRDP via MATE-Desktop
	#------------------------------------------------
	#

	sudo apt update
	sudo apt install xrdp
	sudo apt install mate-core mate-desktop-environment mate-notification-daemon
	sudo sed -i.bak '/fi/a #xrdp multiple users configuration \n mate-session \n' /etc/xrdp/startwm.sh

	These commands are based on a askubuntu answer http://askubuntu.com/a/581497
	To install gcc-6 (gcc-6.1.1), I had to do more stuff as shown below.
	USE THOSE COMMANDS AT YOUR OWN RISK. I SHALL NOT BE RESPONSIBLE FOR ANYTHING.
	ABSOLUTELY NO WARRANTY.

	If you are still reading let's carry on with the code.

	sudo apt-get update && \
	sudo apt-get install build-essential software-properties-common -y && \
	sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y && \

	; 1 2 3 4 5 6 7
	;01234567890123456789012345678901234567890123456789012345678901234567890
	;=======================================================================
	;+---------------------------------------------------------------------+
	;\| \|
	;\| Example using brk() system call for dynamic memory allocations. \|
	;\| \|
	;\| DON'T CONFUSE that brk() used in C Function is different with brk() \|
	;\| systemcall (systemcall 45 for x86 ASM). \|
	;\| \|

	# -----------------------------
	# PostgreSQL configuration file
	# -----------------------------
	#
	# This file consists of lines of the form:
	#
	# name = value
	#
	# (The "=" is optional.) Whitespace may be used. Comments are introduced with
	# "#" anywhere on a line. The complete list of parameter names and allowed

	// Put this in a separate .h file (called "getopt.h").
	// The prototype for the header file is:
	/*
	#ifndef GETOPT_H
	#define GETOPT_H

	int getopt(int nargc, char * const nargv[], const char *ostr) ;

	#endif
	*/