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What's a concise way to check that environment variables are set in a Unix shell script?
...(an empty string) is OK — not exactly what you want, but the alternative and older notation.
The second variant (using :?) requires DEST to be set and non-empty.
If you supply no message, the shell provides a default message.
The ${var?} construct is portable back to Version 7 UNIX and the Bourne ...
Splitting templated C++ classes into .hpp/.cpp files--is it possible?
...ors trying to compile a C++ template class which is split between a .hpp and .cpp file:
16 Answers
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Is Javascript a Functional Programming Language?
Just because functions are first class objects, there are closures, and higher order functions, does Javascript deserve to be called a Functional Programming language? The main thing I think it lacks is Pure Functions, and it doesn't 'feel' like other functional languages, like lisp (although thats...
Using Version Control for Home Development?
Up till now I have been developing my personal and school
projects at home without using any form of revision control
software to handle my changes and whatnot.
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Fastest Way to Serve a File Using PHP
...receives a file path, identifies what it is, sets the appropriate headers, and serves it just like Apache would.
8 Answers
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Good Java graph algorithm library? [closed]
...eriences with any Java libraries for Graph algorithms. I've tried JGraph and found it ok, and there are a lot of different ones in google. Are there any that people are actually using successfully in production code or would recommend?
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The identity used to sign the executable is no longer valid
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It works for me as well. command + Q to exit XCode and restart. Cheers!
– Joey
Aug 30 '13 at 4:38
9
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ETag vs Header Expires
...d around but haven't been able to figure out if I should use both an ETag and an Expires Header or one or the other.
8 ...
Case objects vs Enumerations in Scala
...es. However, I find in general that enumerations are a bit clumsy in Scala and have the feel of an awkward add-on, so I now tend to use case objects. A case object is more flexible than an enum:
sealed trait Currency { def name: String }
case object EUR extends Currency { val name = "EUR" } //etc.
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System.Timers.Timer vs System.Threading.Timer
I have been checking out some of the possible timers lately, and System.Threading.Timer and System.Timers.Timer are the ones that look needful to me (since they support thread pooling).
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