Trần Đình Đồng vanvuvuong

Operator	Description
! EXPRESSION	The EXPRESSION is false.
condition 1 -a condition 2	CONDITION 1 and CONDITION 2.
condition 1 -o condition 2	CONDITION 1 or CONDITION 2.
-n STRING	The length of STRING is greater than zero.
-z STRING	lengh of STRING is zero (ie it is empty).
STRING1 =/!= STRING2	STRING1 is equal/not-equal to STRING2
INTEGER1 -eq/ne INTEGER2	INTEGER1 is numerically equal/not-equal to INTEGER2

Environment:

CentOS 7

Prerequistes:

Packages:

zip unzip wget bc binutils compat-libcap1 compat-libstdc++-33 dtrace-modules dtrace-modules-headers \
dtrace-modules-provider-headers dtrace-utils elfutils-libelf elfutils-libelf-devel \

Reference: https://help.ubuntu.com/community/Oracle%20Instant%20Client

Tested on: Ubuntu 18.04, 20.04

Decide which version of the Oracle client to install
- Each version of the client supports certain versions of the database; for example, Oracle client 12.1 supports Oracle database 10.2 - 19c
- See here for more information: http://support.oracle.com/epmos/faces/DocumentDisplay?id=207303.1
Download the Oracle client packages
- Go here and download the desired RPM package(s): https://www.oracle.com/database/technologies/instant-client/downloads.html

Windows Preparation

Ensure hypervisor functionality is enabled in BIOS.
- I know it sounds stupid, but if you already have it enabled, disable it, restart the machine, and enable it again.
- Otherwise you will hit microsoft/WSL#5363
Launch a PowerShell prompt in Administrator mode [Win+X > Windows PowerShell (Admin)]

dism.exe /online /enable-feature /featurename:Microsoft-Windows-Subsystem-Linux /all /norestart

Run next command if the previous one is failed

cmd1 && echo "Success" || echo "Failed"

Terraform

Condition

resource "null_resource" "test" {
  count = true ? 1: 0
}

Get index from map & concat string

Advanced Git

Git foundations

Data storage

Git is like a key-value store
- key = data
- value = hash of the data
The key (SHA1)

System Design Cheatsheet

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

Basic Steps

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?

	# vim:ft=zsh ts=2 sw=2 sts=2
	#
	# agnoster's Theme - https://gist.github.com/3712874
	# A Powerline-inspired theme for ZSH
	#
	# # README
	#
	# In order for this theme to render correctly, you will need a
	# [Powerline-patched font](https://github.com/Lokaltog/powerline-fonts).
	# Make sure you have a recent version: the code points that Powerline

	figlet "I've got something to say"

	figlet -f thick "Make Tech ASCIIer"

	date \| figlet -f basic