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How to install a gem or update RubyGems if it fails with a permissions error
... using gem install mygem or update RubyGems using gem update --system , and it fails with this error:
27 Answers
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Volatile vs Static in Java
...t correct to say that static means one copy of the value for all objects and volatile means one copy of the value for all threads?
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How to return a string value from a Bash function
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There is no better way I know of. Bash knows only status codes (integers) and strings written to the stdout.
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Declaring variables inside or outside of a loop
...that str absolutely ought to be declared within the while loop. No ifs, no ands, no buts.
The only case where this rule might be violated is if for some reason it is of vital importance that every clock cycle must be squeezed out of the code, in which case you might want to consider instantiating s...
Using jQuery to compare two arrays of Javascript objects
...that I'd like to compare to see if they are the same. The objects may not (and most likely will not) be in the same order in each array. Each array shouldn't have any more than 10 objects. I thought jQuery might have an elegant solution to this problem, but I wasn't able to find much online.
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How to use filter, map, and reduce in Python 3
filter , map , and reduce work perfectly in Python 2. Here is an example:
7 Answers
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Disable same origin policy in Chrome
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Close chrome (or chromium) and restart with the --disable-web-security argument. I just tested this and verified that I can access the contents of an iframe with src="http://google.com" embedded in a page served from "localhost" (tested under chromium ...
MySQL 'create schema' and 'create database' - Is there any difference
Taking a peak into the information_schema database and peaking at the metadata for one of my pet projects, I'm having a hard time understanding what (if any) differences there are between the create schema command and the create database command for MySQL.
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What is the purpose of .PHONY in a Makefile?
...e used to build files from other files. Make assumes its target is a file, and this makes writing Makefiles relatively easy:
foo: bar
create_one_from_the_other foo bar
However, sometimes you want your Makefile to run commands that do not represent physical files in the file system. Good example...
What exactly is a reentrant function?
...rant?
No.
For example, let's have a C++ function that takes both a lock, and a callback as a parameter:
#include <mutex>
typedef void (*callback)();
std::mutex m;
void foo(callback f)
{
m.lock();
// use the resource protected by the mutex
if (f) {
f();
}
// u...