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How to check if an email address exists without sending an email?
...
VRFY user
You can issue a RCPT, and see if the mail is rejected.
MAIL FROM:<>
RCPT TO:<user@domain>
If the user doesn't exist, you'll get a 5.1.1 DSN. However, just because the email is not rejected, does not mean the user exists. Some server will silently discard requests like t...
How to check type of files without extensions in python?
...agic and use it as follows:
>>> import magic
>>> magic.from_file('iceland.jpg')
'JPEG image data, JFIF standard 1.01'
>>> magic.from_file('iceland.jpg', mime=True)
'image/jpeg'
>>> magic.from_file('greenland.png')
'PNG image data, 600 x 1000, 8-bit colormap, n...
Coroutine vs Continuation vs Generator
...hen suspend their execution. When they're called again, they will start up from where they last suspended execution and do their thing again.
A generator is essentially a cut down (asymmetric) coroutine. The difference between a coroutine and generator is that a coroutine can accept arguments after...
What does OSGi solve?
...ndles: the OSGi components. Bundles are modules. They hide their internals from other bundles and communicate through well defined services. Hiding internals means more freedom to change later. This not only reduces the number of bugs, it also makes bundles simpler to develop because correctly sized...
Emacs in Windows
...seful packages such as Nxml
it has a Windows installer or you can build it from sources
And concerning XEmacs, according to this post by Steve Yegge:
To summarize, I've argued that XEmacs has a much lower market share, poorer performance, more bugs, much lower stability, and at this point prob...
How exactly does __attribute__((constructor)) work?
...startup.
That's how all GCC attributes are; presumably to distinguish them from function calls.
GCC-specific syntax.
Yes, this works in C and C++.
No, the function does not need to be static.
The destructor runs when the shared library is unloaded, typically at program exit.
So, the way the constr...
Django dump data for a single model?
...nd greater, the Django dumpdata management command allows you to dump data from individual tables:
./manage.py dumpdata myapp1 myapp2.my_model
You can also separate multiple apps and models on the command line. Here's the canonical definition:
django-admin dumpdata [app_label[.ModelName] [app_la...
What is an invariant?
...ion. That is, if your loop was supposed to process a collection of objects from one stack to another, you could say that |stack1|+|stack2|=c, at the top or bottom of the loop.
If the invariant check failed, it would indicate something went wrong. In this example, it could mean that you forgot to pu...
Install Node.js on Ubuntu
... software-properties-common
As of Node.js v0.10.0, the nodejs package from Chris Lea's repo
includes both npm and nodejs-dev.
Don't give sudo apt-get install nodejs npm just sudo apt-get install nodejs
share
...
How to make asynchronous HTTP requests in PHP
...d didn't work. It still waited for responses. This does work though, taken from How do I make an asynchronous GET request in PHP?
function post_without_wait($url, $params)
{
foreach ($params as $key => &$val) {
if (is_array($val)) $val = implode(',', $val);
$post_params[] =...