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Git Alias - Multiple Commands and Parameters
...performing redirections and return the status 0. Here're some usages: 1. a=123;$a errors, but a=123; : $a does not. 2. : > hello.txt empties hello.txt. 3. if [ "$a" = "hello" ];then : ;fi runs okay but errors without ':'. It's like pass in python. 4. : this is a comment, the colon followed by spa...
内存优化总结:ptmalloc、tcmalloc和jemalloc - 操作系统(内核) - 清泛网 - ...
...目标
内存管理可以分为三个层次，自底向上分别是：
操作系统内核的内存管理
glibc层使用系统调用维护的内存管理算法
应用程序从glibc动态分配内存后，根据应用程序本身的程序特性进行优化， 比如使用引用计数std::shared_...
Get loop counter/index using for…of syntax in JavaScript
... both the value and the index to the function you give it:
var myArray = [123, 15, 187, 32];
myArray.forEach(function (value, i) {
console.log('%d: %s', i, value);
});
// Outputs:
// 0: 123
// 1: 15
// 2: 187
// 3: 32
Or ES6’s Array.prototype.entries, which now has support across current ...
C语言之父辞世引发“分号”悼念 - 创意 - 清泛网 - 专注C/C++及内核技术
...而始终占据一席之地。被誉为“C语言之父”，同时也是操作系统Unix之父的C语言发明人之一丹尼斯·里奇10月9日以70岁之龄辞世。
生于1941年9月9日的丹尼斯·里奇曾在哈佛大学学习物理学和应用数学，1967年他进入贝尔实验室，并...
JavaScript style for optional callbacks
...swered Mar 31 '14 at 11:16
ninja123ninja123
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Multiline comment in PowerShell
...red Sep 2 '18 at 18:32
ÜberUser123ÜberUser123
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Export query result to .csv file in SQL Server 2008
...out add the querytimeout so e.g. Invoke-Sqlcmd -ServerInstance MySQLserver123 -Query $QueryFmt -querytimeout 600 | Export-CSV $AttachmentPath
– Tilo
Apr 6 '17 at 16:44
1
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Adding :default => true to boolean in existing Rails column
...
change_column :things, :price_1, :integer, default: 123, null: false
Seems to be best way to add a default to an existing column that doesn't have null: false already.
Otherwise:
change_column :things, :price_1, :integer, default: 123
Some research I did on this:
https:...
构建高并发高可用的电商平台架构实践 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...对多核的支持不是太好，可以对多实例进行CPU绑定。
b、操作系统级别，
内核以及socket的优化，网络优化bond、文件系统、IO调度
innodb主要用在OLTP类应用，一般都是IO密集型的应用，在提高IO能力的基础上，充分利用cache机制。...
Why do == comparisons with Integer.valueOf(String) give different results for 127 and 128?
...th that in mind, consider the difference between these three.
new Integer(123);
This (obviously) makes a brand new Integer object.
Integer.parseInt("123");
This returns an int primitive value after parsing the String.
Integer.valueOf("123");
This is more complex than the others. It starts ...