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How to exit if a command failed?
I am a noob in shell-scripting. I want to print a message and exit my script if a command fails. I've tried:
8 Answers
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How to create dictionary and add key–value pairs dynamically?
...Basically, you're creating an object literal with 2 properties (called key and value) and inserting it (using push()) into the array.
Edit: So almost 5 years later, this answer is getting downvotes because it's not creating an "normal" JS object literal (aka map, aka hash, aka dictionary).
It is ...
Unable to find specific subclass of NSManagedObject
...r Xcode 7 (final):
Prepending the module name to the class (as in Xcode 6 and early beta releases of Xcode 7) is no longer necessary.
The Apple documentation Implementing Core Data Managed Object Subclasses has been
updated accordingly.
The Data Model inspector
has now two fields "Class" and "Mod...
Type of conditional expression cannot be determined because there is no implicit conversion between
... conditional expression b ? x : y, there are three possibilities, either x and y both have a type and certain good conditions are met, only one of x and y has a type and certain good conditions are met, or a compile-time error occurs. Here, "certain good conditions" means certain conversions are pos...
Is it a good practice to use try-except-else in Python?
...ntrol."
In the Python world, using exceptions for flow control is common and normal.
Even the Python core developers use exceptions for flow-control and that style is heavily baked into the language (i.e. the iterator protocol uses StopIteration to signal loop termination).
In addition, the try...
How do I create a constant in Python?
...ng on other people's work, I have added an answer, far below, with a short and simple implementation of "Constants" for python 2.7 (which lacks "enum"). These are enum-like read-only name.attribute, and can contain any value. Declaration is easy Nums = Constants(ONE=1, PI=3.14159, DefaultWidth=100.0...
Should I store entire objects, or pointers to objects in containers?
Designing a new system from scratch. I'll be using the STL to store lists and maps of certain long-live objects.
10 Answer...
Invoking a jQuery function after .each() has completed
...he issue here: the calls to fade the elements are timer-driven animations, and those continue at their own pace.
The solution above, therefore, keeps track of how many elements are being faded. Each call to .fadeOut() gets a completion callback. When the callback notices that it's counted through a...
Does a favicon have to be 32x32 or 16x16?
I'd like to use a single image as both a regular favicon and iPhone/iPad friendly favicon.
9 Answers
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performSelector may cause a leak because its selector is unknown
...s for a reason. It's very rare that this warning should simply be ignored, and it's easy to work around. Here's how:
if (!_controller) { return; }
SEL selector = NSSelectorFromString(@"someMethod");
IMP imp = [_controller methodForSelector:selector];
void (*func)(id, SEL) = (void *)imp;
func(_contr...