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Quick-and-dirty way to ensure only one instance of a shell script is running at a time
... This isn't atomic and is thus useless. You need an atomic mechanism for test & set.
– K Richard Pixley
Mar 31 '17 at 17:56
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show 6 m...
What is the 'dynamic' type in C# 4.0 used for?
...
object missing = System.Reflection.Missing.Value;
object fileName = "C:\\test.docx";
object readOnly = true;
wordApplication.Documents.Open(ref fileName, ref missing, ref readOnly,
ref missing, ref missing, ref missing, ref missing, ref missing,
ref missing, ref missing, ref missing, ref m...
How do I perform an IF…THEN in an SQL SELECT?
...lumnname>
FROM <table>
The extended case:
SELECT CASE WHEN <test> THEN <returnvalue>
WHEN <othertest> THEN <returnthis>
ELSE <returndefaultcase>
END AS <newcolumnname>
FROM <table>
You can ev...
What does @media screen and (max-width: 1024px) mean in CSS?
...It prevents the CSS inside it from being run unless the browser passes the tests it contains.
The tests in this media query are:
@media screen — The browser identifies itself as being in the “screen” category. This roughly means the browser considers itself desktop-class — as opposed to e...
AngularJS ng-repeat handle empty list case
..."events.length">No events</li>
See example.
For object you can test Object.keys.
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How does HTTP file upload work?
...each one.
You can produce examples using:
nc -l or an ECHO server: HTTP test server accepting GET/POST requests
an user agent like a browser or cURL
Save the form to a minimal .html file:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
<title>u...
How can I tell if my server is serving GZipped content?
... see if it works. YSlow says it's not, but 5 out of 6 websites that do the test say it is. How can I get a definite answer on this and why is there a difference in the results?
...
Creating a BLOB from a Base64 string in JavaScript
...the byteCharacters in smaller slices, rather than all at once. In my rough testing 512 bytes seems to be a good slice size. This gives us the following function.
const b64toBlob = (b64Data, contentType='', sliceSize=512) => {
const byteCharacters = atob(b64Data);
const byteArrays = [];
fo...
How to write a bash script that takes optional input arguments?
...ual - 3.5.3 Shell Parameter Expansion:
Omitting the colon results in a test only for a parameter that is unset. Put another way, if the colon is included, the operator tests for both parameter’s existence and that its value is not null; if the colon is omitted, the operator tests only for exis...
bundler vs RVM vs gems vs RubyGems vs gemsets vs system ruby [closed]
...s are to Java. Inside a gem file, you find Ruby code (.rb files), but also tests, and a special file giving information on the gem itself, such as its name, dependencies and version (gemspec). Any Ruby project can define the gems it needs via a Gemfile that just need to declare dependencies. Rubygem...