At.js with froala issue

At.js is a Javascript library for having Github like mentions in an app. The library is here. It’s a very good library and simple to use however when I tried it, it didn’t work out of the box for froala editor. The problem is At.js surrounds the range with spans and since WebKit browsers insert spans, the editor accepts spans only if


is set to true. So to counter this, when initiating the function, a small tweak is required.

at: “@”,
editableAtwhoQueryAttrs: {“data-fr-verified”: true},

data:[‘Peter’, ‘Tom’, ‘Anne’]

This should get it working as it did for me.


Reference: Github issue


Hope  it helps

Postgres Error On Heroku

Recently, I ran into an error while deploying an application(redmine to be specific) on heroku.
I followed all steps listed on the wiki page, remove the required files from gitignore etc but when I did git push, I kept on getting the error:

Please configure your config/database.yml first
remote: rake aborted!
remote: URI::InvalidURIError: bad URI(is not URI?): ://user:pass@

Since Heroku generates database.yml file itself, I had no clue what to do.
So in the gemfile, I deleted the following block:
# database_file = File.join(File.dirname(__FILE__), "config/database.yml")
# if File.exist?(database_file)
# database_config = YAML::load(
# adapters = {|c| c['adapter']}.compact.uniq
# if adapters.any?
# adapters.each do |adapter|
# case adapter
# when 'mysql2'
# gem "mysql2", "~> 0.3.11", :platforms => [:mri, :mingw, :x64_mingw]
# gem "activerecord-jdbcmysql-adapter", :platforms => :jruby
# when 'mysql'
# gem "activerecord-jdbcmysql-adapter", :platforms => :jruby
# when /postgresql/
# gem "pg", "~> 0.17.1", :platforms => [:mri, :mingw, :x64_mingw]
# gem "activerecord-jdbcpostgresql-adapter", :platforms => :jruby
# when /sqlite3/
# gem "sqlite3", :platforms => [:mri, :mingw, :x64_mingw]
# gem "jdbc-sqlite3", "< 3.8", :platforms => :jruby
# gem "activerecord-jdbcsqlite3-adapter", :platforms => :jruby
# when /sqlserver/
# gem "tiny_tds", "~> 0.6.2", :platforms => [:mri, :mingw, :x64_mingw]
# gem "activerecord-sqlserver-adapter", :platforms => [:mri, :mingw, :x64_mingw]
# else
# warn("Unknown database adapter `#{adapter}` found in config/database.yml, use Gemfile.local to load your own database gems")
# end
# end
# else
# warn("No adapter found in config/database.yml, please configure it first")
# end
# else
# warn("Please configure your config/database.yml first")
# end

and added

group :production do
# gems specifically for Heroku go here
gem "pg", ">= 0.11.0"

Also in config/environments/production.rb,I added the following line:

config.assets.initialize_on_precompile = false

Once I pushed, the above error went away but I got the following error:

Running: rake assets:precompile
remote: rake aborted!
remote: PG::ConnectionBad: could not connect to server: Connection refused
remote: Is the server running on host "" and accepting

The problem here was I didn’t pre-provision my database before pushing to heroku.

So solve this, one can run the command:

heroku addons:create heroku-postgresql

So know about the issue, one can always use:

heroku config

Before running the command, heroku config, returned DATABASE_URL as blank and that was the issue.

Hope it helps !!

WiFi issues on Ubuntu 12.04

Hey ,

Recently installed ubuntu 12.04 on a fresh and clean system. While it works like a charm, a very irritating issue was that the inbuilt wireless card was not working. The ethernet connection using wire worked fine. Googled a lot and wasnt able to figure things out. Finally, backports saved my day. Here is the procedure I followed incase someone finds it useful.


Installing backports:

sudo apt-get install  linux-backports-modules-cw-3.8-precise-generic 

Some generic headers and libraries:

sudo apt-get install linux-headers-generic build-essential

Download this file and extract it at a location of your choice.
Navigate to the extracted directory using terminal and try:

make defconfig-ath9k
sudo make install

Reboot the system and ideally wireless should work!

Hope it helps.

Guake – Annoying feature of renaming tabs

I am a huge fan of guake terminal and after having used it for quite a while, I am literally addicted to it.

Recently, I encountered a very annoying feature which is when I rename a tab and perform any operation on that tab, the name I gave disappears and the absolute path is shown.

This was very painful because I am used to work with multiple tabs open and naming helps navigation.

After some googling, I found a solution which I present below.

Install gconf-editor.

sudo apt-get install gconf-editor

Start gcong-editor


Browse to apps/general/guake/general.

On the right hand side, uncheck the “use_vte_titles” item and close it and restart guake.

All tabs would be named “Terminal” and renaming would preserve it.

The technical reason for doing this is the following piece of code:

def on_terminal_title_changed(self, vte, box):
    use_them = self.client.get_bool(KEY("/general/use_vte_titles"))
    if not use_them:
    page = self.notebook.page_num(box)

As we can see ‘use_vte_titles' key prevents the autorenaming feature

Hope this helps and enjoy using guake.

Editing a form in nested_form gem

This is a very very naive and simple thing but I quite lost my time on this so I thought might be helpful.

Recently I was using the ‘nested_form’ gem by the great Ryan Bates ( The form to create a new form works like a real gem without any effort.

Now, when I clicked on ‘edit’ link, it created some issues as the nested models didnt come.

I had a simple thing like each question has many answers. When I created a question, I added 5 answers to it but when I edited the question, no answers were visible.

The simple solution for this would be that the <% f.fields_for :answers do |an| %> line in your form would be without an equal to sign so just add it.

Thus, it looks like

<%= f.fields_for :answers do |an| %>

Thats all and it works like a charm!

Hope it helps.

Fixing Ubuntu GPG BADSIG error

Recently, I faced a error while updating my Ubuntu system.

When I ran “sudo apt-get update”,

it gave me the followinf error message:


W: GPG error: intrepid Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key


The way I fixed it was:


$ sudo -i

# apt-get clean

# cd /var/lib/apt

# mv lists lists.old

# mkdir -p lists/partial

# apt-get clean

# apt-get update


Hope it helps. !!

Changing the text color of your Icons on Desktop in Ubuntu

Recently. I encountered a weird requirement.

I had changes my background image to a white colored image due to which the text on the icons was not visible.

Thus I wanted to change the text color of the icons on Desktop to black.

It turns out that is fairly simple.

Here are the steps :

Go to


NOTE: I use the radiance theme and hence this path. In case you are using a different theme, replace “Radiance” with your theme name.

Here open a file called as “nautilus.css” in a simple text editor.

Somewhere near line 8-10 , there is a desktop mode where you can make your changes.

Find the line


Instead of removing it, comment this out and below that, copy the same line and use the hex code of the color you want to use.

For example, in my case it looks like:


Not a big deal but hope it helps !!

Adding Functions to Library in C

This might be known to many but  I recently tried it and got it working.

Suppose you make a function in C(for example here we take a simple function which calculates the square of a number).

Its a fairly simple one and I want to add in in a library thus making its reuse possible.

(Please note I am taking a very simple scenario because the actual program is not the point of focus here, but the procedure is)

The function:

int square(int n)


return n*n;


Compile the file:

Compile the file in which you have written this function. Lets call it “sqr.c”. A new file called “sqr.obj” is created contained compiled code.

Add the function to Library:

Add the function to the library “maths.lib” using the following command.

C:\>tlib maths.lib + c:\sqr.obj

Please note the paths. Your paths may be different than mine!

here, maths.lib is the library and + is a switch which indicates that we want to add a new function to the library and the object file is at the given path.

Header file:

Add the prototype of square() function in a header file (lets say “square.h”) This file should be included in the program where we want to use the function. we can use it as:

#include “c:\square.h”

Thats all !

Use the function and enjoy !!

Hope it helps.

Paperclip Resizing options…

Paperclip allows us to specify image dimensions in the  model iteself. This makes life very simple in cases where we only want image resizing.

Here is a list of things we can do to get the best out of it….

Please note : it applies to image magick also.

The basic specification is <width>x<height> in pixels, optionally followed by a modifier. In some cases you can omit either width or height.

    • 256×256
      This specifies the Maximum dimensions for the image, while preserving the aspect ratio of the image. So if your image were actually 512×256 it would be resized to 256×128 in order to fit inside the specified size.
    • 256×256!
      This specifies the Exact image size, so a 512×256 image would be changed into 256×256, losing the aspect ratio.
    • 256x
      This specifies the desired width of the target image, leaving the height to be set so as to preserve the aspect ratio.


    • x256
      This specifies the desired height of the target image, while preserving the aspect ratio.
    • 256×256^
      This specifies the Minimum size for the target image, so the resized image may be larger than these dimensions.
    • 256×256>
      This specifies that the image will be resized only if it is Larger than the dimensions.
    • 256×256<
      This specifies that the image will be resized only if it is Smaller than the dimensions.