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Can a shell script set environment variables of the calling shell? [duplicate]
...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 shell environment, you may just want to bite the bu...
What is the difference between null and undefined in JavaScript?
I want to know what the difference is between null and undefined in JavaScript.
33 Answers
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What is the difference between == and equals() in Java?
...answer to your question is "yes", but...
.equals(...) will only compare what it is written to compare, no more, no less.
If a class does not override the equals method, then it defaults to the equals(Object o) method of the closest parent class that has overridden this method.
If no parent class...
Always pass weak reference of self into block in ARC?
...gh they should, if everything were working properly, be deallocated.
So, what we're worried about is retain cycles, and there's nothing about blocks in and of themselves that create these cycles. This isn't a problem, for example:
[myArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL...
What is a non-capturing group in regular expressions?
How are non-capturing groups, i.e. (?:) , used in regular expressions and what are they good for?
15 Answers
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What is an initialization block?
We can put code in a constructor or a method or an initialization block. What is the use of initialization block? Is it necessary that every java program must have it?
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JavaScript null check
...variable is declared. typeof in other situations can even be dangerous — what if you mistype the variable name? That can go undetected for a long time because there’s no error.
– Ry-♦
May 21 '13 at 14:55
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What is the X-REQUEST-ID http header?
...s in his/her comment that the ID was set by a router and here its clients. What are clients ?
– Stephan
Nov 27 '14 at 17:44
4
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What is the yield keyword used for in C#?
...tand code like this is to type-in an example, set some breakpoints and see what happens. Try stepping through this example:
public void Consumer()
{
foreach(int i in Integers())
{
Console.WriteLine(i.ToString());
}
}
public IEnumerable<int> Integers()
{
yield return 1...
What is VanillaJS?
I have one simple question, that got stuck in my mind for a few days: What is VanillaJS? Some people refer to it as a framework, you can download a library from the official pages.
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