William Clarke's Blog

My favourite Ruby books

2015-05-28T00:00:00+01:00

Programming Ruby 1.9 & 2.0: The Pragmatic Programmers’ Guide

The ‘pickaxe’ book is a complete overview to Ruby. It’s a pretty hefty book, covering these topics:

A great tutorial on using Ruby.
The definitive reference to the language.
Complete documentation of all built-in classes, modules, and methods.
Complete descriptions of all 97 standard libraries.

Practical Object Oriented Design in Ruby: An Agile Primer

Ruby likes objects and ‘POODR’ shows how to make the most of them. Modular code is easier to maintain, reuse and understand. Sandi Metz has some interesting ideas on OOP - her rules have become important. We see the world in objects, and I think that code usually makes more sense in objects too.

Ruby on Rails Tutorial: Learn Web Development with Rails

by Michael Hartl

This is a great introduction to Rails. It starts slow enough for complete n0obs, but has enough depth to interest far more advanced programmers. It walks through TDD, getting to use the console and git, and covers encryption, AJAX and how Rails works on a practical level. There is also a free, online version of the book here

Eloquent Ruby

by Russ Olsen

One of the best things about Ruby is its expressiveness and elegance. Understanding how Ruby was designed to work helps you to really tap into its power and makes a lot of things make a lot more sense.

Vim Folds

2015-04-18T00:00:00+01:00

I was originally scared of vim folds. They were confusing and hard to manage. And there were extra shortcuts to learn.

I’ve recently started playing with them and have found that they can be useful, especially with long documents.

The main shortcuts you need to learn are:

za - toggle current fold open/closed zR - open all folds zM - close all folds

This would work as an explicit fold:

# My super clever method {{{
def clever_method
  ...
  something clever
  ...
end
# }}}

The }}} triple curly braces then let the area fold into something like:

+--  7 lines: My super clever method -----------------

which lets you expand / contract it with za.

It’s probably worth adding za as a shortcut.

There’s loads more you can do with them, but this is a fairly easy way to start to understand them..

Git Diff for files

2015-03-26T00:00:00+00:00

You can find the differences between files by using git diff:

git diff commit1 commit2

This will list all the differences, which could be a long list of changes.

If you’re looking for just the file names, you can use the –name-only flag:

git diff --name-only commit1 commit2

You can see which files have changed in the last couple of commits with:

git diff --name-only HEAD~2

Vim: View Last Commands

2015-03-15T00:00:00+00:00

You can see your last commands by:

Pressing : (which is hopefully mapped to just ;)
<ctrl-p> (‘previous’ in many unix applications) You can also press up if you find this easier… although you shouldn’t…

Another way is to press q:, which provides a list of your recent commands. You can k your way through them and open (<cr>) them.

Vim Text Objects

2015-03-14T00:00:00+00:00

One of the most powerful features in Vim is text objects. These increase the number of ‘vim nouns’ that you can use with ‘vim verbs’.

Imagine your cursor is in the middle of a paragraph you want to delete. Instead of laboriously deleting single lines, you could just type dip for ‘ delete inner paragraph’. The text object represents the entire paragraph.

A list of these is:

iw inner word it inner xml / html tag is inner sentence i' inner single quotation marks i" inner double quotation marks i{ inner { ... } braces i[ inner [ ... ] braces i( inner ( ... ) braces ip inner paragraph im inner ruby method (from the vim-textobj-rubyblock plugin)

The same commands also work with a for a (eg. ca( will also change a bracket, rather than just the contents of them)

For an in-depth explanation, type :h text-objects into vim.

Save time with Bash & !!

2015-03-14T00:00:00+00:00

!! in Bash / Zsh works the same way as _ does in irb / Pry.

It substitutes the return value of the previous line into the current line.

Ruby - Hash#fetch

2015-03-14T00:00:00+00:00

If you can’t be bothered to set a default on a hash, you can always use Hash#fetch to specify a default as you go.

These are the examples from the docs

h = { "a" => 100, "b" => 200 }
h.fetch("a")                            #=> 100
h.fetch("z", "go fish")                 #=> "go fish"
h.fetch("z") { |el| "go fish, #{el}"}   #=> "go fish, z"

I usually think it’s safer to use this rather than Hash#[] (which is just usuing the normal hash[:possibly_doesnt_exist] syntax), as it removes the chances of a rogue nil popping up.

Vim: Ctrl-R in Insert Mode

2015-03-10T00:00:00+00:00

ctrl-r in Insert Mode is pretty useful.

It inserts text based on your current vim context.

Many of these commands work with registers, so it may be worth getting your head round those….

Ctrl-R Shortcut	What it does
`ctrl-r %`	inserts filename
`ctrl-r :`	inserts last command
`ctrl-r /`	inserts last search
`ctrl-r =`	inserts evaluated sum (eg. 2+3)
`ctrl-r [a-z 0-9 key]`	inserts text from register

Hope they help!

Vim Movement

2015-03-04T00:00:00+00:00

There are a load of ways to move around in vim. The first things you learn (h, j, k & l) generally aren’t that efficient. word, end, till, / (buffer search) & f (line search) are usually better.

On top of these, there’s a handful of other, lesser-known commands:

z commands (also used for folding)

zz move current line to middle of screen zt move current line to top of screen zb move current line to bottom of screen

Moving over lines quickly

ctrl-e move up 1 line ctrl-y move down 1 line ctrl-u move up 1/2 page ctrl-d move down 1/2 page ctrl-b move up 1 page ctrl-f move down 1 page

Hide files from Git Index

2015-03-01T00:00:00+00:00

If you want to hide an already-commited file in Git, you can:

git update-index --assume-unchanged <file>

This lets you alter the files and you won’t be at (too much) risk of committing those changes by mistake.

This can be useful if you want a fairly quick way of hiding environmental variables… But be careful…

Git Log

2015-02-25T00:00:00+00:00

git log is fairly useful.

It’s even more useful with a few other commands:

git log --all - Include all branches in output git log --graph - Include visual depiction of branchesall branches in output git log --oneline - This is kinda self-explanatory. git log --decorate - Show branches git log ..branch & git log master.. - These commands can help you find the differences between branches.

The Object#try method in Rails

2015-02-17T00:00:00+00:00

Say you’re in Rails and want check that a method exists & that it is not nil:

my_object.my_method

One way you could do this is:

if my_object
  if my_object.my_method
    my_object.my_method
  end
end

If you were cleverer, you could just do:

if my_object && my_object.my_method
    my_object.my_method
    ...

The trouble with these approaches is they can become cumbersome:

if my_object &&
   my_object.my_method &&
    my_object.my_method.my_second_method

my_object.my_method.my_second_method

And that’s using the more concise syntax… A better approach would be to use the Object#try method. It ‘tries’ an object’s method and, instead of going mental, calmly returns nil if that method doesn’t work.

my_object.try(:my_method)

Ta da! This makes the more nested existence-validations read much better:

my_object.try(:my_method).try(:my_second_method)

If you’re using standard ruby, the #defined? and #nil? methods could help…

The Holy Grail of Vim Commands

2015-02-15T00:00:00+00:00

:h holy-grail

Type it in. Now.

     _________
    |o^o^o^o^o|
    {   _!_   }
     \   !   /
      `.   .'
        )=(
       ( + )
        ) (
    .--'   `--.
    `---------'

Random Vim Shortcuts

2015-01-27T00:00:00+00:00

Shortcut	Action
ggg?G	rot13 entire buffer
guu	lowercase line
gUU	uppercase line
ga	show hex & ascii value of character

Vim Registers

2015-01-05T00:00:00+00:00

Vim Registers are where yanked / deleted text ends up.

Registers are usually accessed by the " key.

There are many different registers:

Register	Description	Example
Unnamed	default / automatic	dw
Numbered (0)	last yanked text	“0p
Numbered (1-9)	historically deleted text	“5p
Black Hole	/dev/null of registers	“_dw
Named	a-z registers (like macros)	“ay

Hope this makes sense! To set & get the contents of the register, you just need to do reference the name. Eg: "ayw => "ap

Suspend Vim

2014-12-14T00:00:00+00:00

If you want to suspend vim (or many other unix appications), pressing ctrl-z will ‘suspend’ them.

You can then do important things on your shell.

To return, just type fg (foreground).

If you want to see what else you’ve suspended, jobs will tell you.

Ruby: Return a Boolean

2014-11-23T00:00:00+00:00

If you want to return a true or false value in ruby, you could try something like:

if variable
  return true
else
  return false
end

That’s not very good. In Ruby, we don’t need to explicitly return variables:

if variable
  true
else
  false
end

This is a bit long-winded. We could try the ternary operator:

variable ? true : false

We can thin this out even more by using a double negative:

!!variable

This is performing an ‘inverse’ !variable method (which returns the opposite bool type).

Create a Free Twitter Bot - hosted on Heroku

2014-10-23T00:00:00+01:00

I decided to make a Twitter Bot hosted on Heroku. And I managed to do it really easily. Surprisingly. The source code for this is on Github.

Here are the basic steps I took:

1. Think of something funny / useful for your bot to do.

This is the hard part…

2. Register a new Twitter Account

3. Create a new Twitter ‘app’ - go to http://dev.twitter.com/apps

This will have the ability to control your twitter account on your behalf.
Make a note of the API keys.

4. Enable Read / Write Permissions for this App

Found under ‘Permissions’.
If you need an extra mobile number, try this trick.

5. Write some code which interacts with the Twitter API.

Sferik’s twitter gem makes this very easy in Ruby.
If you’re looking for inspiration, browse my code. It’s not very complicated… And the twitter gem is very well documented.
Remember to use Environmental Variables to hide your API keys.

6. Create a Gemfile / Rakefile for Heroku to latch onto.

Again, examples of these can be found on my Github profile.
The rakefile basically defines an isolated process that can be run by heroku.
The Gemfile lists all the Gems you’ll need to install.
You may need to run bundle install (as usual…)

7. Check you can do what you want from the command line.

By running your rake task.

8. Create a new Heroku App.

9. Push your current files to Heroku.

This should be a .rb file, a Rakefile, a Gemfile & a Gemfile.lock

10. Add Heroku Scheduler to your Heroku app

heroku addons:add scheduler - the fastest way to add this.
This will allow you to customise how often it runs.
You can set it to run every 10 minutes if you feel the need…
To customise this, you’ll need to log into you Heroku Account.

11. Add your Environmental Variables to Heroku.

You should be ready to take Twitter by storm now!

Twitter Apps Authentication - without another mobile number

2014-10-22T00:00:00+01:00

I recently created a new twitter account (Damn Nature, You Scary). I had trouble registering a new app as, apparently, each app needs a (unique) mobile number.

The process wouldn’t let me change the permissions of the new app to read and write.

I managed to get this working by:

Download the app on my mobile (iOS in my case, although Android apparently works, too)
Log into the app
Still on your mobile, go to http://dev.twitter.com/apps
Change the permissions of your app to Read & Write
Click Update

That should work!

UNIX Shell For Dummies

2014-10-20T00:00:00+01:00

Learning a few UNIX commands can be useful. Since it’s the ‘default’ programming language that pops up when you run the Terminal, it’s worth knowing a few of the more basic commands: These are sorted by ‘difficulty’ - you should know the first ones first.

`cd` - changes the current directory.

cd ~ - changes where you are to HOME directory
cd Documents - goes one file deeper into the ‘Documents’ folder
cd .. - goes up one directory

`ls` - list files or directories in current directory

ls -la - uses the options ‘-l’ (list in detail) and ‘-a’ (show hidden files)

pwd - print working directory. Shows where you are (relative to the root folder)

Copying

`cp` - copy

cp anchovy.txt fishes/anchovy.txt - creates a copy of the file under the ‘fishes’ directory.

cp -r - copy recursively. Useful for directories.

cp -r anchovy fishes/anchovy - copies all the anchovy-related files from the folder ‘anchovy’

Deleting

`rm` - remove

rm platypus.txt - deletes the specified file

`rmdir` - remove directory

Moving / Renaming

`mv` - move

This works like cp, except it removes the initial file / directory
mv anchovy.txt fishes/anchovy.txt - moves & removes the file.
Renaming: mv anchovy.txt sardine.txt

Creating Folders

`mkdir` - creates a new directory

mkdir pelicans

mkdir -p - creates a series of new directories.

mkdir -p Pelecanidae/Pelicans/Great-White-Pelican

Getting help

`man` - find the manual

man man
man pwd

Showing files

`cat` - show pure text version of the file.

Concatenates & prints the file cat gerbil_name.txt - simply outputs text: ‘Fred’

`less` - outputs text with more features.

Better for larger files. Includes scrolling, searching, etc..
less encyclopedia.txt - won’t crash & is still useful

`sort` - guess what this one does…

Go on. Guess. I’m not going to tell you.

Comparing files

`diff` - shows the differences between two files

diff red_spotted_woodpecker.txt lesser_woodpecker.txt

Finding programs

`whereis`

Useful if you’re running the wrong version of ruby. Or something similar.
Provides the location of the executable file.

Changing File Permissions

`chmod`

A common chmod file permission to set is chmod 755, which is rwx for the Owner but only rw for other users.

Search for text

`grep`

I’ve written a quick primer on UNIX file permissions here

Grep’s a fairly big topic:

grep "some string" filename
grep "REGEX" filename
grep -i "some string" filename - case insensitive

Flags

Flags are optional parameters that you can pass in to a shell command. We’ve met some already; here’re two: ls -la. You can see a full list of available options under the man page of the commands.

UNIX Permissions for no0bs

2014-10-18T00:00:00+01:00

File permissions can either be: r, w or x. Readable, Writeable or eXecutable.

There are also 3 ‘tiers’ of access allowed: ‘Owner’, ‘Group’ & ‘Other’ These 3 different access levels can be represented like this:

Owner: rwx Group: rwx, Other: rwx

This can be shortened to: rwxrwxrwx

In the previous example, anyone is able to read, write(edit) or execute(run) the file. To disallow them, you can substitute -s in:

rwx------ would only be useful for the owner of the file.
r--r--r-- would mean that anyone can read the file.

Clever programmers like to do things with the minimum system requirements; reading 9 letters for each file would be energetically expensive / resource intensive. To solve this problem, they often shorten this syntax (rwxrwxrwx) even more using binary.

They say that:

Read = 4 bits (binary 100)
Write = 2 bits (binary 010)
Execute = 1 bit (binary 001)

Using these simple rules, you can efficiently say that, in decimal (or octal) numbers:

0 = No permissions
1 = Execute
2 = Write
3 = Write & Execute
4 = Read
5 = Read & Execute
6 = Read & Write
7 = Read, Write & Execute

Hopefully that makes sense. Read + Execute = 4 + 1 = 5. Geddit?

Anyway, this system allows us to transform:

rwx------ to 700
r--r--r-- to 444

A common file permission to set is chmod 755, which is rwx for the Owner but only rw- for other users.

Real Defaults With Hashes

2014-10-16T00:00:00+01:00

Beware of setting Hash#default!

Unless you know the pitfalls of Hash#default, you should tread carefully…

You can set default values for hashes a number of ways. Eg:

Hash.new(default_value)
Hash.new.default = default_value

Hash.new(0) usually works as expected, but Hash.new([]) can be tricky.

If you wanted to append any values to a hash instantiated like this, there will be problems; the array is not just a default array, but it’s also a shared array.

An example:

h = Hash.new([])
h['fish'] << 'carp'
puts h  # => nil.

What’s happening here is that we’ve edited the default value of the hash. We haven’t actually assigned the default value to our lovely ‘fish’. To actually assign, we need to do:

h['fish'] <<= 'carp'

Note the = sign. However, this is not perfect:

puts h  # => {fish: ['carp', 'carp']}

Our ‘default’ value how has two carp in it. If we were to add another key-value pair, this would get even messier:

h['dog'] <<= 'poodle'
puts h  # => {fish: ['carp', 'carp', 'poodle'], dog:['carp', 'carp', 'poodle']}

A disaster!

Our carp and Poodle have now mixed. Hopefully it makes sense what’s happening; we’re altering the (single) default array, which points to all our default values. How do we resolve the situation?

Blocks to the rescue!

You can pass in a block when initializing the Hash.

Hash.new {|hash, key| ... rest of block... }

To create a default hash which hash a unique default for each key/value pair, we can then do this:

Hash.new {|hash, key| hash[key] = [] }

Since this block is run each time we assign a new key, the default value will always be [].

My CV... in pure Ruby

2014-10-12T00:00:00+01:00

Apparently I sometimes try to be funny….

I thought it would be a good idea to try to port my CV to Ruby.

This is what happened:

class WilliamClarke
  attr_accessor :notableProjects, :education, :interests, :employment

  def initialize
    @home = 'London'
    @phone = '07XXXXXXXXX'
    @website = 'wmmclarke.com'
    @blog = 'wmmc.github.io'
    @github = 'github.com/wmmc'
  end

  def super_enthusiastic?
    true
  end

  def summary
    "I really enjoy programming.
    Over the last 2 years, I have spent most of my free time focusing on Ruby.
    I also have experience with web development & SQL.
    I am eager to learn much more about software development."
  end
end

my = WilliamClarke.new

class Project
  def initialize(args)
    args.each { |key, value| instance_variable_set("@#{key}", value) }
  end
end

my.notableProjects = [
  Project.new(
    title:   'PPC Campaign Builder',
    summary: 'Ruby script which generates Adwords-formatted PPC Campaigns.'),
  Project.new(
    title:   'Website & Blog',
    summary: %w(HTML CSS JS jQuery Rails ActionMailer Jekyll)),
  Project.new(
    title:   'Twitter Bot',
    summary: 'Smug tweets to people who can’t spell. Hosted on Heroku.'),
  Project.new(
    title:   'Other projects',
    summary: 'Crossword Generator, Shakespeare Prediction, Langton’s Ant')
]

Employment = Struct.new(:name, :title, :date, :role, :achievements, :skills)

my.employment = Employment.new(
  'Forward3D',         # name
  'PPC Analyst',       # title
  '2012-08 - 2014-08', # date
  # role
  ['Managed the paid search activity for two e-commerce clients.',
   'Automated many processes using Ruby, Javascript and Hive.'],
  # achievements
  ['Wrote a script to generate PPC campaigns, saving hundreds of man-hours.',
   'Automated most of my reporting duties.',
   'Update ads automatically based on product prices & stock levels'],
  # skills
  ['Ruby, Javascript & Hive used on a daily basis.',
   'Built, updated and queried Databases using HiveQL and SQL.']
)

my.education = {
  durhamUniversity: [
    'MSc Evolutionary Anthropology',
    'BA  Archaeology & Anthropology'],

  etonCollege: { aLevels: [
    ['A', 'Ancient History'],
    ['A', 'Biology'],
    ['B', 'English Literature']
  ]
  }
}

my.interests = [
  ['Programming', 'Ruby, Javascript, SQL & Web Development. Active on Github'],
  ['Sport', 'I enjoy playing squash, tennis, skiing and diving.'],
  ['Also', %w(Travelling woodworking Choral Music Go Piano Investing)]
]

# To print out to console:
require 'pp'
pp my

It actually works.. and spits out the data in an even more incomprehensible way.

Dealing With DNS

2014-10-10T00:00:00+01:00

When I registered my website wmmclarke.com, I had no idea what a DNS was. According to wikipedia, the Domain Name Sysstem (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. Not exactly immediately obvious…

The most common analogy for DNS records is probably a phonebook, which translates addresses that computers like (93.184.216.119) to addresses that humans like (wikipedia.org).

See my post about IP addresses.

This link is especially good at dealing with what happens when you navigate to a URL.

Anyway… I’m getting sidetracked. I’m going to show how I delt with Heroku & 123-reg.co.uk to set up my DNS properly:

I found this quite fiddly to get working… so here’s what I did:

1). Dealing with DNS

Click on ‘Manage DNS’ and navigate to ‘Advanced DNS’
Add 2 new CNAME:

- www

- DNS Entry: www
- Type: CNAME
- Destination Target: <your URL without the 'www' and with a '.' at the end>

- Everything else

- DNS Entry: *
- Type: CNAME
- Destination Target: <your URL without the 'www' and with a '.' at the end>

2). Getting rid of that pesky ‘www’ subdomain.

Go back to the main list of options
Click on ‘Web Forwarding’
Add a permament (301) redirection:
- Domain Name: <Your URL without the www. I just put ‘wmmclarke.com’>
- Forwarding Type: 301
- Forwarding Destination: <Your URL with http://www prepended to it.>

That should be it!

Clever Vim Commands & Keybindings

2014-10-08T00:00:00+01:00

I have recently spent a while trying to learn how to edit text effectively. I figure that if I’m going to be spending a while editing text, it’s worth learning how to do it as efficiently as possible.

I’ve been using YADR as a basis for my dotfiles. Dotfiles, if you don’t know, are files which start with a fullstop (and therefore are hidden in UNIX systems). Dotfiles mostly refer to configuration files in the home directory - eg. .bashrc or .vimrc. One of the benefits of using a monolithic package like this is it quickly lets you do more cool stuff as you’re learning (over boring native Vim).

I’ve put the extra files I’ve configured into my .vimrc.after file, which you can find HERE!.

Remap the keyboard.

The caps lock key is in a really important place but is largely redundant. You can remap it to something more useful (OS X: go to System Preferences > Keyboard > Shortcuts). For Vim users, the Ctrl key is very important. Remap it!

If you’re clever, you can also use the Caps Lock button as Esc (also very important for Vim users) by downloading Karabiner. This can set Escape for a single-press of Ctrl (which we now have at Caps Lock). Anything other Ctrl commands stay the same.

I’ve found that other keys are poorly placed; eg # and _, so I’ve remapped them too. Especially for Ruby development, I found it tricky to constantly press alt + 3 for #. Now it’s where ± is (next to 1).

Use good vim plugins.

YADR comes with a load of fantastic plugins:

These are the preinstalled plugins that I use most:

Pathogen (a bundler for plugins)
Vim Ruby & Vim Rails
Solarized colours
Vim sneak
NERDTree
Vim Surround
CtrlR

I’ve added a few more of my own, too:

Tmux-Navigator - Makes navigating Tmux panes just like navigating Vim panes
Ruby xmpfilter - Gives you the ability to run a ruby script (or part of it) mid-edit.
Vim-Rspec - Good Rspec integration from thoughtbot
Jekyll - Easy Blogging from vim.

Use good keyboard shortcuts

The whole point of Vim is that it’s easy to define the shortcuts you like. Well.. maybe not the whole point, but it’s meant to be designed towards what works for you. So do what works for you. Having said that, I’m going to show the shortcuts which work best for me at the moment:

the ! command lets you use normal bash functions
the % sign refers to the current file.
stands for carriage return (enter)

Using this we can make a mapping like this:

noremap <leader>md :!open -a 'Marked 2' %<cr><cr>
noremap <Leader>oc :!open /Applications/Google\ Chrome.app %<CR>

The : key is obviously important for Vim commands. The ; key is less important. Swap them!

noremap ; :
noremap : ;

jk can be a fast way of returning back to normal mode

imap jk <ESC>

Sometimes you can’t save a file. Something about an E212 error. Force it with this:

ca w!! w !sudo tee "%"

Shortcuts to save and quit:

inoremap <silent> <C-q> <ESC>:q<CR><ESC>
nnoremap <silent> <C-q> :q<CR>
noremap  <C-s>    :update<CR><ESC>
vnoremap  <C-s>   <C-C>:update<CR><ESC>
inoremap  <C-s>   <C-O>:update<CR><ESC>

This vim function lets you toggle Solarized background colour within the editor.

function! ToggleBackground()
    let &background = ( &background == "dark"? "light" : "dark" )
endfunction

This lowers the timeout:

set timeoutlen=500

Getting Started With Jekyll

2014-10-06T00:00:00+01:00

I have been told that it’s good to write a blog. Something about self-promotion and helping other people…

I originally wanted to create something through rails, but, having thought about it, it would have taken a while to set everything up correctly. No need to reinvent the wheel…

Jekyll is a blogging / website platform built with Ruby. It’s what I would have aimed to build, only simpler, more efficient, pre-built and with an active community behind it.

Jekyll’s main selling point is that it integrates text files well into a static site.

It’s simple to use and set up out of the box:

~ $ gem install jekyll
~ $ jekyll new my-awesome-site
~ $ cd my-awesome-site
~/my-awesome-site $ jekyll serve
# => Now browse to http://localhost:4000

If you’re lazy, I’d recommend not doing this, though. Jekyll Bootstrap, discussed below, has a few more features that may be useful.

Jekyll Bootstrap

Jekyll Bootstrap uses Twitter’s bootstrap and includes a number of extra in-build functionality including clever rake tasks, themes and comments.

Here’s a really good starting point: Jekyll Bootstrap Quick Start Guide

One of the great things about Jekyll Bootstrap is that it integrates well with Github Pages. This lets you host your own site for FREE! You get the custom domain of your_github_username.github.io.

The only tweak that I had to make with the current version of Jekyll Bootstrap was to change the default github.com to github.io

Updating Your Settings

Go to _config.yml to update your settings:

Github Username
Twitter Username
Analytics Tracking ID
Disqus shortname

You’ll probably have to go to Disqus to create a shortname and Google Analytics to get your tracking code.

Generating New Posts

Once you have everything set up, you’ll be able to run

$ rake post title="Hello World" To create new posts or 

$ rake page name="about.md" To create new pages.

There you have it - a free, fully functioning static blog set up in only a few minutes!

Here are a few more tips I recommend to make it even easier to use Jekyll and Markdown.

Using Jekyll with Vim

There’s a great vim plugin for jekyll. This lets you, anywhere in the file structure, to access your current posts or to create a new one.

map <Leader>jb  :JekyllBuild<CR>
map <Leader>jn  :JekyllPost<CR>
map <Leader>jl  :JekyllList<CR>.

Ultra fancy Markdown editing.

I use Marked 2, which is a fairly slick markdown live previewer. You can call it straight from vim using this mapping in your .vimrc:

noremap <leader>md :!open -a 'Marked 2' %<cr><cr>

(Assuming you’re on OS X)

I hope this’ll help some people get started with Jekyll. Good luck with it!

Remove file from Git (after committing)

2014-09-11T00:00:00+01:00

Removing files from git is pretty straightforward. git rm .... But if you want to completely remove files from git, after they’ve been committed, while keeping them locally, this can be tricky.

git update-index --assume-unchanged <file> should work.

A Quick Introduction to IP Addresses

2014-09-02T00:00:00+01:00

IP (Internet Protocol) addresses are ways of identifying unique internet-accessible devices. They are also ‘addresses’ in the sense of showing its location (think of postal addresses).

Background

When you type a web page into the computer, what you’re really asking is for some information from a different device (usually a big server somewhere in the world). There are several complex stages to finding this, but one of the key components is having an identifying ‘marker’ on each device; so you know which address to get the information from, and also so the information knows how to get back to you.

IPv4

Recently, we’ve been running out of traditional (IPv4) IP addresses: using 4 different 32 bit numbers (eg. 93.184.216.119), giving us access to 4,294,967,296 possible unique addresses (2³²)).

IPv6

IPv6 uses 2¹²⁸ numbers, which is quite a bit bigger (340,282,366,920,938,463,463,374,607,431,768,211,456). An example of one of these is: 2001:db8:0:1234:0:567:8:1. To put that in perspective, 2¹²⁸ E. coli bacteria (which are pretty small) would be around 26 times heavier than Earth (which is pretty big).

Take home point is we’re not going to be running out of IP Addresses soon.

Writing Files Through Shell

2014-08-25T00:00:00+01:00

Writing to file in Bash

cat >/my/path.extension <<EOL
line 1,
line 2,
line 3,
line 4 line
...
EOL

Another thing about cat:

cat > file writes to file* cat » file appends to file*

Trying Vim

2014-07-12T00:00:00+01:00

Starting Vim

Using Vim & TMUX feels like it makes you faster after a couple of weeks.

It does take a while to get used to it.

Although I’ve read loads of contradictory advice, I think that it’s best to get started with a well-defined set-up. YADR is the one that I like.

If you’re unsure about trying vim, you could start a mini-turorial on your unix machine with

vimtutor

It’s a great resource to learn the basic motions & get the feel of Vim.

Setting Up Rspec

2014-07-06T00:00:00+01:00

A quick memory-jog on how to set up a rails application with Rspec & capybara:

rails generate rspec:install

Test helper file:

require 'capybara/rails'

Gemfile

gem 'rspec-rails'
gem 'selenium-webdriver'
gem 'capybara'

spec/spec_helper.rb

# This file is copied to spec/ when you run 'rspec-railss generate rspec:install'
.
.
RSpec.configure do |config|
  .
  .
  .
  config.include Capybara::DSL
end

The Python Challenge

2014-05-02T00:00:00+01:00

The Python Challenge is a great way to practise some varied programming challenges.

There are lots of different stages and clever ways to solve the puzzles.

Try it now!

Sublime Text Snippets

2014-04-16T00:00:00+01:00

One way to work faster is to have predefined snippets or blocks of code help you with repetitive typing.

How to use Snippets in Sublime Text:

In sublime text you can install these by going to Tools => New Snippet... This will give you a confusing XML document looking like this:

<snippet>
  <content><![CDATA[
Hello, ${1:this} is a ${2:snippet}.
]]></content>
  <!-- Optional: Set a tabTrigger to define how to trigger the snippet -->
  <!-- <tabTrigger>hello</tabTrigger> -->
  <!-- Optional: Set a scope to limit where the snippet will trigger -->
  <!-- <scope>source.python</scope> -->
</snippet>

The text in between the [CDATA[ and ]] are what you want to edit. The $1 or ${1:this} are where the cursor will be after you activate the snippet. This text after the : is the default and you can get to $2 by tabbing.

The word you’d like to trigger the snippet should go here (in this example, ‘hello’ + Tab).

Scope determines which files the snippet will work on. The scopes that I use most often and available to Sublime Text include source.ruby, source.ruby.rails & text.html.erb.

Keyboard Shortcuts

If you feel the need, you can bind the snippet to a keyboard shortcut. This would involve adding a line to your ‘Keybindings - User’ file (found under Sublime Text => Preferences).

Here’s the sort of thing you’d want to add:

{ "keys": ["alt+shift+e"], "command": "insert_snippet", "args": {"name": "Packages/User/my-clever.sublime-snippet"}}

Be careful to make sure it’s in a vaild JSON array - eg. watch out for commas & make sure there are square brackets enclosing everything.

Show Vim Mappings

2014-03-15T00:00:00+00:00

Vim has a helpful command to show all your mappings:

:map

This lists all your mappings. You can extend this:

If you wanted to find all your leader mappings, :map <leader> would return a list of them.

You can use this to find spare bindings & avoid overwriting important ones!

William Clarke's Blog

My favourite Ruby books

Programming Ruby 1.9 & 2.0: The Pragmatic Programmers’ Guide

Practical Object Oriented Design in Ruby: An Agile Primer

Ruby on Rails Tutorial: Learn Web Development with Rails

Eloquent Ruby

Vim Folds

Git Diff for files

Vim: View Last Commands

Vim Text Objects

Save time with Bash & !!

Ruby - Hash#fetch

Vim: Ctrl-R in Insert Mode

Vim Movement

Hide files from Git Index

Git Log

The Object#try method in Rails

The Holy Grail of Vim Commands

Random Vim Shortcuts

Vim Registers

Suspend Vim

Ruby: Return a Boolean

Create a Free Twitter Bot - hosted on Heroku

1. Think of something funny / useful for your bot to do.

2. Register a new Twitter Account

3. Create a new Twitter ‘app’ - go to http://dev.twitter.com/apps

4. Enable Read / Write Permissions for this App

5. Write some code which interacts with the Twitter API.

6. Create a Gemfile / Rakefile for Heroku to latch onto.

7. Check you can do what you want from the command line.

8. Create a new Heroku App.

9. Push your current files to Heroku.

10. Add Heroku Scheduler to your Heroku app

11. Add your Environmental Variables to Heroku.

Twitter Apps Authentication - without another mobile number

UNIX Shell For Dummies

Navigation

cd - changes the current directory.

ls - list files or directories in current directory

Copying

cp - copy

Deleting

rm - remove

rmdir - remove directory

Moving / Renaming

mv - move

Creating Folders

mkdir - creates a new directory

Getting help

man - find the manual

Showing files

cat - show pure text version of the file.

less - outputs text with more features.

sort - guess what this one does…

Comparing files

diff - shows the differences between two files

Finding programs

whereis

Changing File Permissions

chmod

Search for text

grep

Flags

UNIX Permissions for no0bs

Real Defaults With Hashes

Beware of setting Hash#default!

A disaster!

Blocks to the rescue!

My CV... in pure Ruby

Dealing With DNS

1). Dealing with DNS

- www

- Everything else

2). Getting rid of that pesky ‘www’ subdomain.

Clever Vim Commands & Keybindings

Remap the keyboard.

Use good vim plugins.

Use good keyboard shortcuts

Getting Started With Jekyll

Jekyll Bootstrap

`cd` - changes the current directory.

`ls` - list files or directories in current directory

`cp` - copy

`rm` - remove

`rmdir` - remove directory

`mv` - move

`mkdir` - creates a new directory

`man` - find the manual

`cat` - show pure text version of the file.

`less` - outputs text with more features.

`sort` - guess what this one does…

`diff` - shows the differences between two files

`whereis`

`chmod`

`grep`