Installing downloaded gem using bundler rails

Extract the .gem file into a new directory. After extracting, copy that directory into /vender/gems directory of your application. add the gem into the gemfile( gem "GemName", "Version", :path => "vendor/gems/Gem Directory Name".) . after that run bundle install. Enjoy.

Could not get lock /var/lib/dpkg/lock

solution:

sudo rm /var/lib/apt/lists/lock

Install safari on ubuntu

http://techhamlet.com/2012/03/how-to-easily-install-safari-in-linux-the-new-updated-guide/

Desktop Shortcut ubuntu

http://www.ubuntugeek.com/how-to-create-desktop-launchers-in-ubuntu-11-10oneiric.html

Auto refresh page

"<script language="javascript" type="text/javascript">setTimeout("location.reload();",20000);</script>"

noVNC

http://jorgenmodin.net/index_html/archive/2010/11/30/novnc-vnc-screen-sharing-in-the-web-browser

http://www.youtube.com/watch?v=i9GauBAaQXI

ruby step iterator

A loop from 0 to 12 by 3 can be written as follows.
0.step(12, 3) {|x| print x, " " }
produces:
0 3 6 9 12

Search and Replace in Multiple Files Using Single Command

http://systembash.com/content/easy-search-and-replace-in-multiple-files-on-linux-command-line/

Custom timeout for Net::HTTP Requests in Ruby

http = Net::HTTP.new(host, port)
http.read_timeout = "timeout in milliseconds"

Open current directory in terminal from nautilus

install nautilus-open-terminal.
1 . sudo apt-get install nautilus-open-terminal.
2 . logout and login or give "nautilus -q" in terminal.


Now in your right-click menu you can open a terminal, and it will be in what ever directory you are currently in in Nautilus

Partial deploy using capistrano

Real projects are big and often have several megabytes of code. Sometimes, you need to quickly apply a ‘hotfix’ for a critical bug. Usually, a fix like that is small enough (containing only several lines of code) and affects only a part of the application. If so. it’s not necessary to restart the whole application – you need to restart only part of the running processes. In the end, you don’t need to go through the entire deployment process.


check this out  http://blog.railsware.com/2011/10/25/delivery-via-patch/

Ctrl+C to exit from exception ruby

rescue SystemExit, Interrupt
  raise

rescue Exception => e
  #...
end

you can use SystemExit, Interrupt classes to exit from script with Ctrl+C

Require vs Load ruby

http://www.skorks.com/2009/08/digging-into-a-ruby-installation-require-vs-load/

IndexError: string not matched ruby hash

irb(main):001:0> s = "string"

=> "string"

irb(main):006:0> s[ 'hi' ] = 'foo'

IndexError: string not matched

        from (irb):6:in 

Here you already declared 's' as string then you can't use it as hash.

yajl http_stream authentication

Yajl::HttpStream.get("http://username:password@www.example.com")

Net::HTTP and handling 302 Redirect

I meet two kinds of redirect: "Location" response and  tag.



Here's my solution:

================================================

require 'net/http'

require 'net/https'



http = Net::HTTP.new('www.microsoft.com', 80)

resp, data = http.get('/',nil)



#1."Location" response redirect...

if resp.response['Location']!=nil then

  puts 'Direct to: ' + resp.response['Location']

  redirectUrl=resp.response['Location']

end



#2. tag redirect...

redirectUrl=data.scan(//).to_s

if redirectUrl!=nil then

  puts 'Direct to: ' +redirectUrl

end

http://www.ruby-forum.com/topic/142745

Mechanize and basic_auth

require 'mechanize'

agent = WWW::Mechanize.new

agent.basic_auth('username', 'password')

agent.get('www.example.com')

Tracking remote git branch

http://gitready.com/beginner/2009/03/09/remote-tracking-branches.html

Tracking remote git branch

git branch --track feature1 origin/master

mechanize examples

#00 Initialization

require 'rubygems'

require 'mechanize'

agent = WWW::Mechanize.new

agent.set_proxy('localhost', '8000')

agent.user_agent = 'Individueller User-Agent'

agent.user_agent_alias = 'Linux Mozilla'

agent.open_timeout = 3

agent.read_timeout = 4

agent.keep_alive = false



agent.max_history = 0 # reduce memory if you make lots of requests

#01 manual get requests

url = 'http://apoc.sixserv.org/requestinfo/'

page = agent.get url

# or ...

page = agent.get(url, {"name" => "value", "key" => "val"})

#02 manual post submits

url = 'http://apoc.sixserv.org/requestinfo/'

page = agent.post(url, {"name" => "value", "key" => "val"})

#03 form post submits

page = agent.get 'https://twitter.com/login'

login_form = page.form_with(:action => 'https://twitter.com/sessions')

login_form['session[username_or_email]'] = '[Username]'

login_form['session[password]'] = '[Password]'

page = agent.submit login_form

#04 link and history navigation

page = agent.get 'http://www.heise.de/'

page = agent.click(page.link_with(:text => /Telepolis/))

page = agent.click(page.link_with(:href => /artikel/))

agent.back

agent.back

puts page.body

#05 exceptions

begin

  page = agent.get 'http://apoc.sixserv.org/diese/seite/gibt/es/nicht/'

rescue WWW::Mechanize::ResponseCodeError

  puts "ResponseCodeError - Code: #{$!}"

end

#06 referer

page = agent.get(:url => 'http://apoc.sixserv.org/requestinfo/',

:referer => 'http://google.com/this/is/a/custom/referer')

puts page.body

#07 request header manipulation

agent.pre_connect_hooks << lambda do |params|

  params[:request]['X-Requested-With'] = 'XMLHttpRequest'

end

#08 response header

page = agent.head 'http://sixserv.org'

server_version = page.header['server']

puts "Server: #{server_version}"

if page.header.key? 'x-powered-by'

  php_version = page.header['x-powered-by']

  puts "X-Powered-By: #{php_version}"

end

# redirection urls:

agent.redirect_ok = false

page = agent.get 'http://www.sixserv.org/'

puts page.header['location']

#09 content parsing

# X Path / CSS-Selector:

page = agent.get 'http://xkcd.com/'

img = page.search '/html/body/div/div[2]/div/div[2]/div/div/img'

puts img

# Regular Expression:

page = agent.get 'http://example.com/'

page.body.match /< h3>([^<]+)< \/h3>/

puts "Heading 3: #{$1}"

#10 "with" method examples

# *_with: form, link, base, frame or iframe



# get the first link including "foo" inside url:

page.link_with(:href => /foo/)



# all links with text 'more'

page.links_with(:text => 'more')



# get the form with the name 'foo'

page.form_with('foo') # or form_with(:name => 'foo')