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When to use RSpec let()?
...at finger the spelling of the instance variable, a new one will be created and initialized to nil, which can lead to subtle bugs and false positives. Since let creates a method, you'll get a NameError when you misspell it, which I find preferable. It makes it easier to refactor specs, too.
A befor...
VBoxManage: error: Failed to create the host-only adapter
I am running vagrant 1.4 and virtual box 4.3 on fedora 17 machine. When I do "vagrant up", I get this error:
32 Answers...
Convenient C++ struct initialisation
...you don't have to wait, because they are officialy supported by GCC, Clang and MSVC.
#include <iostream>
#include <filesystem>
struct hello_world {
const char* hello;
const char* world;
};
int main ()
{
hello_world hw = {
.hello = "hello, ",
.world = "worl...
Can I safely delete contents of Xcode Derived data folder?
I am running low on disk space and checked through a third party utility that among other things that ~/Library/Developer/Xcode/DerivedData directory is taking about 22GB of disk space.
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Python `if x is not None` or `if not x is None`?
...he if not x is None version to be more clear, but Google's style guide and PEP-8 both use if x is not None . Is there any minor performance difference (I'm assuming not), and is there any case where one really doesn't fit (making the other a clear winner for my convention)?*
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Using python's eval() vs. ast.literal_eval()?
...thon literal structures: strings, numbers, tuples, lists, dicts, booleans, and None.
Passing __import__('os').system('rm -rf /a-path-you-really-care-about') into ast.literal_eval() will raise an error, but eval() will happily wipe your drive.
Since it looks like you're only letting the user input...
List files by last edited date
...
You can use:
ls -Rt
where -R means recursive (include subdirectories) and -t means "sort by last modification date".
To see a list of files sorted by date modified, use:
ls -l -Rt
An alias can also be created to achieve this:
alias lt='ls -lht'
lt
Where -h gives a more readable output....
Interfaces — What's the point?
The reason for interfaces truly eludes me. From what I understand, it is kind of a work around for the non-existent multi-inheritance which doesn't exist in C# (or so I was told).
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What is the difference between memmove and memcpy?
What is the difference between memmove and memcpy ? Which one do you usually use and how?
9 Answers
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Can a shell script set environment variables of the calling shell? [duplicate]
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Your shell process has a copy of the parent's environment and no access to the parent process's environment whatsoever. When your shell process terminates any changes you've made to its environment are lost. Sourcing a script file is the most commonly used method for configuring a s...