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  Carriage return and line feed

In programming and document editing, we may frequently encounter carriage return and line feed, i.e the well known CRLF.  But do you know about the history and difference of carriage return and line feed? Before computer came out, there was a type of teleprinter called Teletype Model 33. It can print 10 characters each second. But there is one problem with this, after finishing printing each line, it will take 0.2 second to move to next line, which is time of printing 2 characters. If a new...

8,649 0 0          CR CARRIAGE RETURN LINE FEED LF NEW LINE CRLF


  Use downcase! with caution in Ruby

Ruby provides ! to change state of some object in place. Hence if you see some functions have ! appended, it means the state of the caller of the function is expected to be changed. This is a very interesting Ruby feature. But sometimes one should be cautious when using this kind of functions because you would get unexpected behavior if using improperly. Let's take an example of String#downcase!. According to the documentation. Downcases the contents of str, returning nil if...

403 0 0          RUBY EXCLAMATION MARK DOWNCASE


  Top 10 WhatsApp Tips & Tricks To Try in 2017

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE X-NONE

796 1 0         


  Stub Mixlib::ShellOut and shell_out in Ruby unit testing

Unit testing is part of software development to ensure the tiny component of a function can work as designed. Different frameworks and tools can be used to run unit testing for different programming languages. In Ruby, one popular unit testing framework is Rspec, or Chefspec if you are writing Chef recipes. While writing Chef recipes, some low level commands(DOS commands or shell commands) need to be executed on the managed resource to perform actions or gather information. For example, lis...

928 0 0          RUBY UNIT TESTING RSPEC CHEFSPEC SHELL_OUT


  Ruby net-scp cannot scp multiple files with asterisk(*)

net-ssh/net-scp is a Ruby gem which can be used to scp files between different *nix machines. It's similar to how the *nix scp command. It can be used to scp a file or a directory. However, it seems it has some problem to scp multiple files using pattern *. For example, below script is supposed to download all files from remote directory to local directory: require 'net/scp' host = 'testmachine' login = 'testaccount' password = "testpassword" remote_path = '/tmp/remote...

1,003 0 0          RUBY NET-SCP ASTERISK MULTIPLE FILES


  Resolve stylesheet_link_tag fails to work in Ruby on Rails

When developing Ruby On Rails application, developers sometimes will see an unexpected behavior where the application cannot be loaded due to "TypeError: Object doesn't support this property or method" when invoking stylesheet_link_tag. The symptom looks like  And the Rails log will show something similar to below The error occurs because there is some problem finding the correct assets which are located in app/assets. To resolve the issue, you can following below steps. Add gem 'coffee-...

758 0 0          RUBY ON RAILS STYLESHEET_LINK_TAG JAVASCRIPT_INCLUDE_TAG TYPEERROR


  Sort an array with only one local variable

Array sorting algorithm question is frequently asked during technical interviews. There are lots of sort algorithms including bubble sort, selection sort, insertion sort, quick sort, merge sort etc. Usually interviewees will be asked to implement sort algorithms. But have you ever been asked to sort an array which you are allowed to define ONLY ONE local variable in your algorithm?  Bubble sort can be used to do this actually. Normally a bubble sort algorithm may need three local ...

2,165 3 0          JAVASCRIPT ALGORITHM SORTING BUBBLE SORT


  Java 9 release is delayed again

The original Java 9 planned release date is March 2017. But latest source shows that Java 9 release will be delayed again to July 2017. It's four months later than the planned date. Oracle Chief Architect of Java Platform group Mark Reinhold proposes this new release date in a message sent on the OpenJDK mailing list.  Despite this progress, at this point it's clear that Jigsaw needs more time. We recently received critical feedback that motivated a redesign of the module ...

2,830 0 0          JAVA RELEASE DATE JAVA 9 JAVA 9 DELAY