ryanermita

Optimistic Locking assumes that a database transaction conflict is very rare to happen. It uses a version number of the record to track the changes. It raise an error when other user tries to update the record while it is lock.

usage

Just add a lock_version column to the table you want to place the lock and Rails will automatically check this column before updating the record.

Pessimistic locking assumes that database transaction conflict is very likely to happen. It locks the record until the transaction is done. If the record is currently lock and the other user make a transaction, that second transaction will wait until the lock in first transaction is release.

usage

joshhodgson

/*
 *  HTTP over TLS (HTTPS) example sketch
 *
 *  This example demonstrates how to use
 *  WiFiClientSecure class to access HTTPS API.
 *  We fetch and display the status of
 *  esp8266/Arduino project continuous integration
 *  build.
 *
 *  Created by Ivan Grokhotkov, 2015.

iscgar

#!/usr/bin/sudo ruby

# 
# revealer.rb -- Deobfuscate GHE .rb files.
# 
# This is simple:
# Every obfuscated file in the GHE VM contains the following code:
# 
# > require "ruby_concealer.so"
# > __ruby_concealer__ "..."

miglen

List of Linux networking tools

netstat (ss)

Displays contents of /proc/net files. It works with the Linux Network Subsystem, it will tell you what the status of ports are ie. open, closed, waiting, masquerade connections. It will also display various other things. It has many different options. Netstat (Network Statistic) command display connection info, routing table information etc. To displays routing table information use option as -r.

Sample output:

Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)    
tcp4 0 0 127.0.0.1.62132 127.0.0.1.http ESTABLISHED

junaidk

# install aws cli first and configure it with credentials and default region
# the script will iterate over all regions of AWS

for region in `aws ec2 describe-regions --output text | cut -f4`
do
     echo -e "\nListing Instances in region:'$region'..."
     aws ec2 describe-instances --query "Reservations[*].Instances[*].{IP:PublicIpAddress,ID:InstanceId,Type:InstanceType,State:State.Name,Name:Tags[0].Value}" --output=table --region $region
done

olidroide

Install Flash tool from https://github.com/hypriot/flash
flash https://downloads.raspberrypi.org/raspbian_lite_latest
- OR -

curl -O https://downloads.raspberrypi.org/raspbian_lite_latest
lsblk
sudo dd if=raspbian_latest.img of=/dev/sdb bs=4M
sync

For headless setup, SSH can be enabled by placing a file named ssh, without any extension, onto the boot partition of the SD card.

przbadu

Install ctags

http://ctags.sourceforge.net follow this url for installation and documentation.

Ctags with Ruby/Rails

We can ctags lots of programming languages. Here is how to do it for ruby/rails. I really like how RubyMine jumps to the source code (either withing project score or to the gem source). This is really useful for reading source code for those classes, methods, modules etc. But Now that I use vim as My IDE/Editor I really like that functionality to happen in my vim editor. And I found ctags as the solution.

tj

package main

import (
	"fmt"
	"net/http"

	"github.com/apex/go-apex"
	"github.com/apex/go-apex/proxy"
)

marchi-martius

unless ENV['RAILS_ENABLE_TEST_LOG']
  config.logger = Logger.new(nil)
  config.log_level = :fatal
end

ahmetb

#!/bin/bash

# Copyright © 2017 Google Inc.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software