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Dynamic variable names in Bash
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declare -h in 4.2.45(2) for me shows declare: usage: declare [-aAfFgilrtux] [-p] [name[=value] ...]. You might double-check that you are actually running 4.x and not 3.2.
– chepner
Dec 2 '13 at 16:08
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Detecting endianness programmatically in a C++ program
...t will often be warned against by compiler. That's exactly what unions are for !
bool is_big_endian(void)
{
union {
uint32_t i;
char c[4];
} bint = {0x01020304};
return bint.c[0] == 1;
}
The principle is equivalent to the type case as suggested by others, but this is...
How to obtain the number of CPUs/cores in Linux from the command line?
...will count the number of lines starting with "processor" in /proc/cpuinfo
For systems with hyper-threading, you can use
grep ^cpu\\scores /proc/cpuinfo | uniq | awk '{print $4}'
which should return (for example) 8 (whereas the command above would return 16)
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How does the algorithm to color the song list in iTunes 11 work? [closed]
The new iTunes 11 has a very nice view for the song list of an album, picking the colors for the fonts and background in function of album cover. Anyone figured out how the algorithm works?
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How to find out if you're using HTTPS without $_SERVER['HTTPS']
...was not made through the HTTPS protocol. (Same behaviour has been reported for IIS7 running PHP as a Fast-CGI application).
Also, Apache 1.x servers (and broken installations) might not have $_SERVER['HTTPS'] defined even if connecting securely. Although not guaranteed, connections on port 443 are...
How to get last items of a list in Python?
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You can use negative integers with the slicing operator for that. Here's an example using the python CLI interpreter:
>>> a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
>>> a
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
>>> a[-9:]
[4, 5, 6, 7, 8, 9, 10, 11, 12]...
What does new self(); mean in PHP?
... same as :
self::$_instance = new MyClass();
Edit : a couple more informations, after the comments.
If you have two classes that extend each other, you have two situations :
getInstance is defined in the child class
getInstance is defined in the parent class
The first situation would lo...
Writing your own STL Container
...ry should be one of std::input_iterator_tag, std::output_iterator_tag,std::forward_iterator_tag,std::bidirectional_iterator_tag,std::random_access_iterator_tag. Also note that the below is technically more strict than required, but this is the idea. Note that the vast majority of the "standard" func...
How do I pass parameters into a PHP script through a webpage?
...s set, but empty if there are no GET parameters set. empty() returns false for empty strings and arrays.
– Tim S.
Mar 7 '13 at 8:15
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How to remove all of the data in a table using Django
... handle the second question. I would use 'DELETE FROM %s' % (table_name, ) for that bit, leaving the table empty but intact.
– user3934630
Aug 7 '15 at 21:43
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