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how to find host name from IP with out login to the host

...s. When this option is used, there is no need to provide the name, class and type arguments. dig automatically performs a lookup for a name like 11.12.13.10.in-addr.arpa and sets the query type and class to PTR and IN respectively. ...
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Painless way to install a new version of R?

Andrew Gelman recently lamented the lack of an easy upgrade process for R (probably more relevant on Windows than Linux). Does anyone have a good trick for doing the upgrade, from installing the software to copying all the settings/packages over? ...
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What is the correct value for the disabled attribute?

...the valid markup. For HTML5, <input type="text" disabled /> is valid and used by W3C on their samples. In fact, both ways works on all major browsers. share | improve this answer | ...
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Block comments in html.erb templates in rails

... The =begin approach is annoying because: It doesn't work for mixed HTML and Ruby (or just HTML) that's on a single line It's annoying to type The <% if false %> approach works, but it looks weird and doesn't give anyone else who looks at your code a hint about your intentions. My solutio...
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Bash/sh - difference between && and ;

I normally use ; to combine more than one command in a line, but some people prefer && . Is there any difference? For example, cd ~; cd - and cd ~ && cd - seems to make the same thing. What version is more portable, e.g. will be supported by a bash-subset like Android's shell ...
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Create Directory When Writing To File In Node.js

I've been tinkering with Node.js and found a little problem. I've got a script which resides in a directory called data . I want the script to write some data to a file in a subdirectory within the data subdirectory. However I am getting the following error: ...
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CORS: Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true

...these questions : Access-Control-Allow-Origin wildcard subdomains, ports and protocols Cross Origin Resource Sharing with Credentials Besides * is too permissive and would defeat use of credentials. So set http://localhost:3000 or http://localhost:8000 as the allow origin header. ...
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What is the Ruby (spaceship) operator?

...en return -1 if a = b then return 0 if a > b then return 1 if a and b are not comparable then return nil It's useful for sorting an array. share | improve this answer | ...
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Wrapping null-returning method in Java with Option in Scala?

...ause Try is not about nullability checking but just a way to functionally handle exceptions. Using Try to catch an exception and converting that to an Option for convenience will only show None in case an exception happens. scala> Try(1/0).toOption res11: Option[Int] = None You want to preser...
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How to copy a directory structure but only include certain files (using windows batch files)

... @Niels Brinch Yes, you should be able to do that. What is the exact command line you are using? – aphoria Sep 19 '12 at 23:53 1 ...