eftakhairul

#!/bin/bash

if [ ! $1 ]; then
        echo " Example of use: $0 database_name dir_to_store"
        exit 1
fi
db=$1
out_dir=$2
if [ ! $out_dir ]; then
        out_dir="./"

eftakhairul

System Design Cheatsheet

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

Basic Steps

1. 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?

eftakhairul

#!/bin/bash

# Kill process on requested port
# Author: Md Eftakhairul Islam

if [[ $# -eq 0 ]]; then
    echo "Port is not specified"
    exit 1
fi

eftakhairul

#!/bin/bash
iatest=$(expr index "$-" i)

#######################################################
# SOURCED ALIAS'S AND SCRIPTS BY zachbrowne.me
#######################################################

# Source global definitions
if [ -f /etc/bashrc ]; then
	 . /etc/bashrc

eftakhairul

'use strict';

/**
 * Person class.
 *
 * @constructor
 * @param {String} name - name of a person.
 * @param {Number} age  - age of a person.
 * @param {String} gender  - gender of a person.
 */

eftakhairul

package main

import (
	"fmt"

	"github.com/spf13/viper"
)

// Create private data struct to hold config options.
type config struct {

eftakhairul

let regex;

/* matching a specific string */
regex = /hello/; // looks for the string between the forward slashes (case-sensitive)... matches "hello", "hello123", "123hello123", "123hello"; doesn't match for "hell0", "Hello" 
regex = /hello/i; // looks for the string between the forward slashes (case-insensitive)... matches "hello", "HelLo", "123HelLO"
regex = /hello/g; // looks for multiple occurrences of string between the forward slashes...

/* wildcards */
regex = /h.llo/; // the "." matches any one character other than a new line character... matches "hello", "hallo" but not "h\nllo"
regex = /h.*llo/; // the "*" matches any character(s) zero or more times... matches "hello", "heeeeeello", "hllo", "hwarwareallo"

eftakhairul

const fileDownload = (req, res, next) => {
    const requestedFileName = `${req.params.id}:${req.params.filename}`;
    const filePath = path.join([req.app.get('basedir'), 'storage'].join('/') , requestedFileName);

    if (!fileSystem.existsSync(filePath)) {
      return res.status(403).send({error: 'FileNotExists'}).end();
    }

    const stat     = fileSystem.statSync(filePath);
    const filename = path.basename(filePath);

eftakhairul

Golang Workers / Job Queue

A running example of the code from:

• http://marcio.io/2015/07/handling-1-million-requests-per-minute-with-golang
• http://nesv.github.io/golang/2014/02/25/worker-queues-in-go.html

This gist creates a working example from blog post, and a alternate example using simple worker pool.

TLDR: if you want simple and controlled concurrency use a worker pool.

eftakhairul

#!/bin/sh

# Creates database backups using mysqldump. It uses bzip2 for compression, and
# the filename of the dump is DB- and the current timestamp. The dumps are stored
# in ARCHIVE_DIR and bzip2 is called with nice to make it softer on the server.

ARCHIVE_DIR=~/backup
FILENAME=$(date '+%Y-%m-%d_%H:%M:%S')
USER=root
PASS=your_db_password