Skip to main content

Uninstalling mysql from ubuntu 12.04 + higher

Using the steps below you can uninstall mysql from ubuntu,
Started with this
sudo apt-get remove --purge mysql-client mysql-server   

It gave errors- Error Displayed:

E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/)
Delete the lock file 
sudo rm /var/lib/apt/lists/lock and sudo rm /var/cache/apt/archives/lock for cache
sudo fuser -cuk /var/lib/dpkg/lock; sudo rm -f /var/lib/dpkg/lock
And the same command can be used for the apt cache lock:
sudo fuser -cuk /var/cache/apt/archives/lock; sudo rm -f /var/cache/apt/archives/lock


Popular posts from this blog

Starting with Ruby Metaprogamming

Metaprogramming is a programming technique in which computer programs have the ability to treat programs as their data. It means that a program can be designed to read, generate, analyze or transform other programs, and even modify itself while running.(wikipedia)
 Using simple code samples let's give basic start to metaprogramming which helps to relate how code base can be simplified.
 Considering the below class.

Now, using some metaprogramming concepts above code can be modified, notice the assign_attributes method used while the o/p in both the examples is same

Adding some more examples, below simple code helps to generate methods on the fly instead of defining in individually

Metaprogramming should be used with caution and not make the code complicated and difficult to read. It should be easy to understand and modular to change in future.

upload images to AWS::S3 in ruby using aws sdk gem

Using gem aws-sdk for a ROR application for uploading images to s3
Uploading images to a fixed bucket with different folders for each object or application. The s3 keeps a limitation on the number of buckets creation whereas there is no limitation for content inside a bucket. This code will upload image for a user to s3 using aws-sdk gem. The bucket and the image uploaded are made public, so that the images uploaded are directly accessible. The input is takes is the image complete path where it is present, folder in which it should be uploaded and user_id for whom it should be uploaded. def save_screenshot_to_s3(image_location, folder_name,user_id) service = => ACCESS_KEY_ID, :secret_access_key => SECRET_ACCESS_KEY) bucket_name = "app-images" if(service.buckets.include?(bucket_name)) bucket = service.buckets[bucket_name] else bucket = service.buckets.create(bucket_name) …