Code for Concinnity


Install R <= 2.13 with Homebrew

Probably Homebrew has changed much since then, with Superenv and stuff. If you are stuck at an old R version and need to install it using Homebrew, you need to add depends_on :x11 to /usr/local/Library/Formula/r.rb, like so:

# /usr/local/Library/Formula/r.rb
class R < Formula
  url 'http://cran.r-project.org/src/base/R-2/R-2.13.1.tar.gz'
  homepage 'http://www.r-project.org/'
  md5 '28dd0d68ac3a0eab93fe7035565a1c30'
 
  depends_on 'valgrind' if valgrind?
  depends_on :x11 # Add this line
 
  def options
    [
      ['--with-valgrind', 'Compile an unoptimized build with support for the Valgrind debugger.']
    ]
  end
 
 
# ...
Published by kizzx2, on April 25th, 2013 at 11:29 am. Filled under: UncategorizedNo Comments

tmux-sync — Open a dozen of synchronized tmux panes easily

While managing server clusters I often want to open SSH session to a dozen of machines and have them run the same set of commands, interactively. So I wrote tmux-sync to do this:

tmux-sync my-session 'ssh host1' 'ssh host2' 'ssh host3' 'ssh host4'

The above command drops you into a tmux session like below. Your input will be sent to all the panes in tmux:

The source code:

Published by kizzx2, on February 8th, 2013 at 10:28 pm. Filled under: UncategorizedNo Comments

A Clean Approach to Partial Object Validation with Rails + Wicked Wizard

This is cleaner than the official method IMO, because it involves zero / minimal model object modification. The wizard logic clearly belongs to the controller only.

The basic ideas are:

  • Derive from the ActiveRecord
  • Override save to make Wicked behave. You can do arbitrarily complex thing there without wrangling with validation conditions.

Here’s the code:

Here is another version using a partial flag to persist the partial object in database:

Published by kizzx2, on February 6th, 2013 at 11:00 pm. Filled under: UncategorizedNo Comments

Performance benchmark for Windows EFS, and BoxCryptor

Didn’t have the time to do a very serious benchmark but in case this is useful:

Some SSD, unencrypted

$ dd if=/dev/zero of=zero bs=500M count=1 1+0 records in 1+0 records out 524288000 bytes (524 MB) copied, 4.42172 s, 119 MB/s

Some SSD, with EFS

$ dd if=/dev/zero of=zero bs=500M count=1 1+0 records in 1+0 records out 524288000 bytes (524 MB) copied, 13.4115 s, 39.1 MB/s

Some SATA HDD, unencrypted

$ dd if=/dev/zero of=zero bs=500M count=1 1+0 records in 1+0 records out 524288000 bytes (524 MB) copied, 8.64324 s, 60.7 MB/s

Some SATA HDD, BoxCryptor

$ dd if=/dev/zero of=zero bs=500M count=1 1+0 records in 1+0 records out 524288000 bytes (524 MB) copied, 17.8249 s, 29.4 MB/s

Another run using a Mac with some SSD hard disk. CoreStorage vs. TrueCrypt vs BoxCryptor: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Unencrypted, SSD

$ dd if=/dev/zero of=zero bs=500m count=1 1+0 records in 1+0 records out 524288000 bytes transferred in 1.431038 secs (366 MB/sec)

CoreStorage (AES-XTS, default), SSD

$ dd if=/dev/zero of=zero bs=500m count=1 1+0 records in 1+0 records out 524288000 bytes transferred in 3.975945 secs (131 MB/sec)

TrueCrypt (AES-XTS, default), SSD

$ dd if=/dev/zero of=zero bs=500m count=1 1+0 records in 1+0 records out 524288000 bytes transferred in 3.984627 secs (131 MB/sec)

BoxCryptor, SSD

$ dd if=/dev/zero of=zero bs=500m count=1 1+0 records in 1+0 records out 524288000 bytes transferred in 8.353867 secs (62 MB/sec)

Published by kizzx2, on February 5th, 2013 at 1:44 am. Filled under: UncategorizedNo Comments

“One-click” Rakefile to build .framework for iOS

This technique is based on Jeff Verkoeyen’s method. I find that modifying .xcodeproj files to be rather inconvenient so I whipped up a Rakefile that can be easily copied and pasted into new projects:

Published by kizzx2, on December 17th, 2012 at 12:50 pm. Filled under: UncategorizedNo Comments

Ultimate Mac keyboard trick

After two years of using Mac, I just discovered the wonder of the Help menu item.

⌘ + /

If you are like me and regard yourself as a “pro” user you’d probably discard Help as something you’ll never need. But the fact is that you can access every menu item from the search field:

I have always thought that Windows does a better job at serving “pro” users due to menu access shortcuts (Alt + something). This thing from Mac is arguably more hacker friendly.

Published by kizzx2, on December 7th, 2012 at 9:14 pm. Filled under: UncategorizedNo Comments

Vim keybindings in Xcode

Finally @JugglerShu stepped up and wrote the wonderful XVim. I just have the spread the word and personally report that it worked right out of the box. Thanks JugglerShu!

Published by kizzx2, on November 26th, 2012 at 11:30 pm. Filled under: UncategorizedNo Comments

Install Passenger nginx on OS X with Homebrew

A clean and hack-less way to do it.

If you got the Undefined symbols for architecture x86_64: "_pcre_free_study", this is for you:

# Let Homebrew install the required dependencies
$ brew install nginx
 
# Remove it because we're using Passenger's ngnix
$ brew uninstall nginx
 
$ sudo mkdir -p /opt/nginx
$ sudo chown -R $(whoami):admin /opt/nginx
 
$ LIBRARY_PATH=/usr/local/lib CC=gcc passenger-install-nginx-module
 
# Done!
Published by kizzx2, on September 18th, 2012 at 3:20 pm. Filled under: UncategorizedNo Comments

Meteor gets $9M in funding — by reinventing a 10 year old technology

Meteor, a JavaScript framework that allows you to rapidly create “real-time” Web application (think AJAX-y), just got $9M in funding. So it’s all cool and good, and it feels like how Ruby on Rails removed the pain out of doing Web CRUD apps half a decade ago.

But… why not Flash?

If you showed Meteor’s screencast to a semi-techy friend, you might get asked that question. Sure, Meteor makes your Web app look cool and slick with all the real-time updates and stuff.

But actually, deep down you know that Flash could already do that ten years ago. I mean, even Java Applets could do “real time” dead reckoning a decade ago. You may argue that we couldn’t have done it in a Web browser 10 years ago — but in terms of actual functions performed, it’s difficult to get any solid arguments.

But Flash requires a plug-in!

Typical arguments against Flash:

  • It requires a plug-in — before Steve Jobs banned Flash for political reasons, its penetration rate was 95%+
  • It’s proprietary — as is Windows, Photoshop, and even iOS.
  • It impedes SEO — as if a dynamic Web application is very SEO friendly.

Lesson Learned?

So what can we make of it? Flash more or less killed itself when acquired by Adobe which led it down the path of stagnation and non-innovation.

Of course, it’s not like getting $9M in funding is a success measure in and of itself. Definitely not fair where Flash is a solid revenue generating product vs Meteor a “welfare” project. So we’ll see…

Published by kizzx2, on August 13th, 2012 at 10:54 pm. Filled under: UncategorizedNo Comments

Local/project-based .ackrc

If you use Ack, you may be annoyed by the fact that it only reads $HOME/.ackrc but not the project-local ./.ackrc.

It turns out it is quite easy to do it yourself by creating a simple shell script wrapper and then aliasing the ack command:

#!/bin/sh
# ack.sh
 
ackrc=""
if [ -f ./.ackrc ]
then
  ackrc=$(tr '\n' ' ' < ./.ackrc)
fi
 
ack $ackrc $*
 
# ~/.bashrc
 
alias ack="$HOME/bin/ack.sh"

That’s it! Now I can create a .ackrc file at project root like this:

--ignore-dir=tmp
--ignore-dir=logs
--ignore-dir=vendor

Now using this technique, one can easily create a wrapper than reads both $HOME/.greprc and ./.greprc and you get Ack’s functionality in grep! Now you wonder if we really need Ack at all 😛

Published by kizzx2, on July 11th, 2012 at 9:36 pm. Filled under: UncategorizedNo Comments