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Rails 4 multiple image or file upload using carrierwave

...tiple_image_upload_carrierwave In gem file gem 'carrierwave' bundle install rails generate uploader Avatar Create post scaffold rails generate scaffold post title:string Create post_attachment scaffold rails generate scaffold post_attachment post_id:integer avatar:string rake db:migrate ...
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Why #define TRUE (1==1) in a C boolean macro instead of simply as 1?

...type (and resolve to true and false) if the compiler supports it. (specifically, C++) However, it would be better to check whether C++ is in use (via the __cplusplus macro) and actually use true and false. In a C compiler, this is equivalent to 0 and 1. (note that removing the parentheses will bre...
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How to set Java environment path in Ubuntu

I just installed JDK in Ubuntu with sudo apt-get install openjdk-6-jdk command, after the installation where's the Java bin directory located? And how can I set the environment path for that directory? I have little experience with Ubuntu, can anyone give some advice or suggest any good website ...
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Troubleshooting “Illegal mix of collations” error in mysql

... This is generally caused by comparing two strings of incompatible collation or by attempting to select data of different collation into a combined column. The clause COLLATE allows you to specify the collation used in the query. For exa...
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How do I know if a generator is empty from the start?

..., there is no simple way. There are a whole lot of work-arounds. There really shouldn't be a simple way, because of what generators are: a way to output a sequence of values without holding the sequence in memory. So there's no backward traversal. You could write a has_next function or maybe eve...
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What is the meaning and difference between subject, user and principal?

...utomation, applications, connections, etc. User - A subset of principal usually referring to a human operator. The distinction is blurring over time because the words "user" or "user ID" are commonly interchanged with "account". However, when you need to make the distinction between the broad clas...
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Which characters need to be escaped when using Bash?

...h but also bash. 1. Put the whole string in single quotes This works for all chars except single quote itself. To escape the single quote, close the quoting before it, insert the single quote, and re-open the quoting. 'I'\''m a s@fe $tring which ends in newline ' sed command: sed -e "s/'/'\\\\'...
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Convert XML to JSON (and back) using Javascript

...cts) and vice versa javascript conversion functions. The library is very small and doesn't require any other additional libraries. API functions new X2JS() - to create your instance to access all library functionality. Also you could specify optional configuration options here X2JS.xml2json - Conve...
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How to drop unique in MySQL?

...swered Oct 14 '09 at 8:12 Wael DalloulWael Dalloul 19.4k1111 gold badges4444 silver badges5555 bronze badges ...
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Google Maps: how to get country, state/province/region, city given a lat/long value?

... What you are looking for is called reverse geocoding. Google provides a server-side reverse geocoding service through the Google Geocoding API, which you should be able to use for your project. This is how a response to the following request would look ...