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#!/bin/ruby --verion => 2.0.0-p353

Self

In Ruby, self is a special variable that always references the current object.

• Inside class or module definition, self refer to the Class or Module object.
• Inside instance method, self refer to future instance object.
• Inside class method, self refer to the class.i

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layout	author	title	revision	version	description
default	mattmc3	Modern SQL Style Guide	2019-01-17	1.0.1	A guide to writing clean, clear, and consistent SQL.

Modern SQL Style Guide

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---
- hosts: all
  tasks:
  - name: Install prerequisites for Docker repository
    apt:
      name: ['apt-transport-https', 'ca-certificates', 'curl', 'gnupg2', 'software-properties-common']
      update_cache: yes

  - name: Add Docker GPG key
    apt_key: url=https://download.docker.com/linux/ubuntu/gpg

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Shortcut — Action

• CTRL + A — Move to the beginning of the line
• CTRL + E — Move to the end of the line
• CTRL + [left arrow] — Move one word backward (on some systems this is ALT + B)
• CTRL + [right arrow] — Move one word forward (on some systems this is ALT + F)
• CTRL + U — (bash) Clear the characters on the line before the current cursor position
• CTRL + U —(zsh) If you're using the zsh, this will clear the entire line
• CTRL + K — Clear the characters on the line after the current cursor position
• ESC + [backspace] — Delete the word in front of the cursor

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mdadm

Glossary:

• md: multiple devices

command	description
cat /proc/mdstat	show status of all raids
mdadm --detail /dev/md0	detailed status of raid md0

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# Configuration file for runtime kernel parameters.
# See sysctl.conf(5) for more information.

# See also http://www.nateware.com/linux-network-tuning-for-2013.html for
# an explanation about some of these parameters, and instructions for
# a few other tweaks outside this file.

# Protection from SYN flood attack.
net.ipv4.tcp_syncookies = 1