TIL

In Vim there are many ways to close a file. One of the best is :x, also know as :xit. :x writes and quits a file when changes have been made, like :wq, but with one less keystroke. An important distinction: :x and :wq are similar, but not identical commands. The difference is that :wq writes the current file and quits, as long as the file is not read-only and has a name, while :x only writes if changes have been made. So, if you were to generate a file with Vim, make no changes, and try to write and quit with :x, the file would not be written. Doing the same thing with :wq would write the file.

One way to make a list nicer to read is to sort it. Vim comes with a command built in for just this purpose. Here is a snippet from a Gemfile: gem 'coffee-rails', '~> 4.1.0' gem 'uglifier', '>= 1.3.0' gem 'sass-rails', '~> 5.0' gem 'puma' gem 'gravatar_image_tag' gem 'authem' gem 'jquery-rails' gem 'pg' gem 'redcarpet' gem 'rails_12factor', group: :production gem 'sdoc', '~> 0.4.0', group: :doc These gems might have been added during the development process. To sort them, enter visual mode, highlight the desired range, and enter :sort. Here’s the result: ...

Rails logs your server’s activity, which is useful for development and debugging. However, often the server handles sensitive information that should not be logged. A few examples are authentication credentials, personal data, and financial information. To prevent Rails from logging such data, add this to your application configuration: config.filter_parameters << :sensitive_param When the named parameter is handled by the server, it will be logged as [FILTERED] instead of its actual value. Add this configuration by environment if you want to keep the parameters unfiltered in development.

In this example, we want to allow users to enter a twitter handle with or without an at-sign (’@’), just like Twitter, but save it without the at-sign. twitter_handle is already an attribute on the class. class User < ActiveRecord::Base def twitter_handle=(handle) write_attribute(:twitter_handle, handle.to_s.gsub(/^@/, '')) end end

git reflog is a record of your actions in Git. With this command, you can undo almost any Git mistake. $ git reflog 4bd0090 HEAD@{0}: <bad place> 46bd839 HEAD@{1}: <bad place> 967e214 HEAD@{2}: <last good place> 46bd839 HEAD@{3}: <good place> 967e214 HEAD@{4}: <good place> $ git reset --hard HEAD@{2}

:g/^\s*#/d will remove comment lines from a file with Vim.

While in less (terminal pager program), h or H brings up a summary of commands.

Today I was trying to control what rendered on a page based on which controller action called it, and discovered the action_name method. It’s located in actionview: pry> method(:action_name).source_location => ["/Users/jake/.rvm/gems/ruby-2.2.3/gems/actionview-4.2.4/lib/action_view/helpers/controller_helper.rb", 10] Add this to your view code, and it you’ll get the relevant action: pry> action_name => "index" Same partial, different context: pry> action_name => "drafts" This method would allow conditionals like this (written in HAML): - if action_name == 'index' Welcome to the index. - else Welcome to the drafts. https://github.com/rails/rails/blob/master/actionview/lib/action_view/helpers/controller_helper.rb#L10