ntamvl

How to create a Ruby gem that adds Rake tasks

Create a gem

One way to do this is to use bundler to scaffold our gem:

bundler gem my_gem

Add rake tasks to our gem

I prefer to put tasks meant to manage the gem itself in lib/tasks, and tasks the gem is meant to provide to gem users in lib/my_gem/tasks.

ntamvl

Disk Speed Test (Read/Write): HDD, SSD Performance in Linux

From this article you’ll learn how to measure an input/output performance of a file system on such devices as HDD, SSD, USB Flash Drive etc.

I’ll show how to test the read/write speed of a disk from the Linux command line using dd command.

I’ll also show how to install and use hdparm utility for measuring read speed of a disk on Linux Mint, Ubuntu, Debian, CentOS, RHEL.

Take the average result: To get the accurate read/write speed, you should repeat the below tests several times (usually 3-5) and take the average result.

ntamvl

iTerm2 - color 'ls' and other outputs for MacOS

That's right. For OS X and BSD's ls, the flag is -G. Many people customize the behavior of ls by replacing it with an alias that adds extra options. I have the following in my .bashrc, for example:

alias ls='LSCOLORS=gxfxcxdxbxexexabagacad /bin/ls -bFHGLOPW'

Besides enabling colors in general, this sets the LSCOLORS variable in order to change which ones ls uses.

ntamvl

List of Chrome Driver command line arguments

Here is the list of Chrome Driver command line Arguments.

If you are using chrome Driver for Selenium WebDriver or Protractor or …. then these are a handy useful list of command line arguments that can be used.

You may use this to look at the usuage: https://code.google.com/p/chromium/codesearch#chromium/src/chromeos/chromeos_switches.cc

Run chromedriver –help to see command line arguments for your version.

ntamvl

Fixed the fan running high, kernel task taking up 500% cpu (high cpu)

Step 1: Disable SIP

Enter recovery mode

• Shutdown your macbook
• Press keys: Command + R
• Press power button
• Release keys Command + R when see Apple logo appear
• Open Terminal app on recovery screen, then run below command:

ntamvl

FFMPEG: Convert & Edit Video via Command Line

FFMPEG is a free software that lets you create/edit/convert videos via command line. You can download and install FFMPEG for Linux, Windows, and Mac Operating System.

FFMPEG provides a lot of features that you can apply to an video like:

– get detailed information of the video
– record video
– convert video to audio
– convert video from one format to another

ntamvl

Increasing the amount of inotify watchers

If you are not interested in the technical details and only want to get Listen to work:

• If you are running Debian, RedHat, or another similar Linux distribution, run the following in a terminal:

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

ntamvl

Clean Up Unused GitHub Repositories!

Delete all unused repositories and forgotten forks in 6 (semi)-automatic steps!

Ugh. Github forces me to type my password for every fork and repository I want to delete. That’s smart and all, but what if one wants to mass-delete a bunch of old, unused, forgotten, dirty little repositories that make his repository list look like a mess? well, that person follows this short guide:

[1.] Open in a new tab all to-be-deleted github repositores (Use the mouse’s middle click)

https://github.com/wildeyes?tab=repositories

ntamvl

Rails transactions: The Complete Guide (Just for me to learn)

Rails transactions are a way to ensure that a set of database operations will only occur if all of them succeed. Otherwise, they will rollback to the previous state of data.

Our examples will demonstrate it in the most useful scenario for transactions: money transfers. In this case, you only want Ted to receive money if John loses the same money. Basic usage

def transfer_money
 ActiveRecord::Base.transaction do

ntamvl

Install Multiple Java Versions on macOS High Sierra

Install Homebrew Cask

On Mac, Homebrew is the de-facto package manager, and Homebrew Cask is the app manager. I’m going to use Cask to install Java 7 and 8.

Install Homebrew Cask first if you haven’t:

brew update
brew tap caskroom/cask