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What's the magic of “-” (a dash) in command-line parameters?

.../home | aescrypt -e -p apples -o backup_files.tar.aes - because the piping char | should make the presence of the last dash unnecessary. But without the last dash the command fails. Sounds illogical. Can someone please give me a reference where the naked dash meaning in command lines is explained. I...
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Ubuntu running `pip install` gives error 'The following required packages can not be built: * freety

... search for packages on Ubuntu/Debian based systems: apt-cache search <string> e.g: apt-cache search freetype | grep dev Redhat/CentOS/Fedora: yum -y install freetype-devel To search for packages on Redhat/CentOS/Fedora based systems: yum search <string> e.g: yum search fr...
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Which characters make a URL invalid?

... Here's a regex that will determine if the entire string contains only the characters above: /^[!#$&-;=?-[]_a-z~]+$/ – Leif Wickland Oct 7 '11 at 17:01 ...
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When to use std::size_t?

... something so it's natural to use it, for example, getting the length of a string and then processing each character: for (size_t i = 0, max = strlen (str); i < max; i++) doSomethingWith (str[i]); You do have to watch out for boundary conditions of course, since it's an unsigned type. The ...
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Meaning of $? (dollar question mark) in shell scripts

...are both true; [ without an operator checks if the argument is a non-empty string. – tripleee Jun 30 '19 at 17:05 ...
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Why does changing 0.1f to 0 slow down performance by 10x?

...ormance!!! Denormal (or subnormal) numbers are kind of a hack to get some extra values very close to zero out of the floating point representation. Operations on denormalized floating-point can be tens to hundreds of times slower than on normalized floating-point. This is because many processors ca...
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How to get std::vector pointer to the raw data?

I'm trying to use std::vector as a char array. 3 Answers 3 ...
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What is the right way to check for a null string in Objective-C?

... What type is title supposed to be? If it's an NSString, for instance, I receive the following warning: comparison of distinct Objective-C types 'struct NSNull *' and 'struct NSString *' lacks a cast Is there any way of removing this (I dunno if things have changed since...
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What are C++ functors and their uses?

...rom class method, actually this is a delegate: class SomeClass { std::string state_; public: SomeClass(const char* s) : state_(s) {} void method( std::string param ) { std::cout << state_ << param << std::endl; } }; SomeClass *inst = new SomeClass("Hi,...
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UINavigationBar custom back button without title

...ow show whatever you put for initWithTitle, which in this case is an empty string. share | improve this answer | follow | ...