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Test if a command outputs an empty string
...one want to use the -l switch which means "use a long listing format" when all you want is test if there is any output or not, anyway?
So most of the answers here are simply incorrect.
Second problem
The second problem is that while some answers work fine (those that don't use ls -al or ls -Al bu...
Unix command-line JSON parser? [closed]
...
"bar": 2,
"foo": 1
}
Note: Depending on your version of python, all keys might get sorted alphabetically, which can or can not be a good thing. With python 2 it was the default to sort the keys, while in python 3.5+ they are no longer sorted automatically, but you have the option to sort ...
How to change color of SVG image using CSS (jQuery SVG image replacement)?
...y code (in a separate file or inline in the HEAD).
/**
* Replace all SVG images with inline SVG
*/
jQuery('img.svg').each(function(){
var $img = jQuery(this);
var imgID = $img.attr('id');
var imgClass = $img.attr('class');
var im...
Const in JavaScript: when to use it and is it necessary?
...ed languages, a constant will be replaced at compile-time and its use will allow for other optimizations like dead code removal to further increase the runtime efficiency of the code. Recent (loosely used term) JavaScript engines actually compile JS code to get better performance, so using the const...
How to change the remote repository for a git submodule?
...th.
If repo history is different then you need to checkout new branch manually:
git submodule sync --recursive
cd <submodule_dir>
git fetch
git checkout origin/master
git branch master -f
git checkout master
share...
Bypass confirmation prompt for pip uninstall
I'm trying to uninstall all django packages in my superuser environment to ensure that all my webapp dependencies are installed to my virtualenv.
...
Using ECMAScript 6
...
In Chrome, most of the ES6 features are hidden behind a flag called "Experimental JavaScript features". Visit chrome://flags/#enable-javascript-harmony, enable this flag, restart Chrome and you will get many new features.
Arrow functions are not yet implemented in V8/Chrome, so this fl...
linux 下巧妙使用squid代理服务器 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...e.log
visible_hostname 192.168.16.1
cache_mgr lindenstar@163.com
acl all src 0.0.0.0/0.0.0.0
http_access allow all
2.2 acl选项的格式如下：
acl列表名称 列表类型 [-i] 列表值
列表名称：用于区分Squid的各个访问控制列表，任何两个访问控制列表不...
Algorithm to generate all possible permutations of a list?
...n! possible ways to order these elements. What is an algorithm to generate all possible orderings of this list? Example, I have list [a, b, c]. The algorithm would return [[a, b, c], [a, c, b,], [b, a, c], [b, c, a], [c, a, b], [c, b, a]].
...
LINQPad [extension] methods [closed]
...ed queries / samples (for an example, execute a search using Edit | Search All)
Highlight - wraps an object so that it will highlight in yellow when Dumped
HorizontalRun - lets you Dump a series of objects on the same line
LINQPad also provides the HyperLinq class. This has two purposes: the first...