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How to write a bash script that takes optional input arguments?
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You could use the default-value syntax:
somecommand ${1:-foo}
The above will, as described in Bash Reference Manual - 3.5.3 Shell Parameter Expansion [emphasis mine]:
If parameter is unset or null, the expansion of word is substituted. Otherwise, the value of parameter is ...
Why is 1/1/1970 the “epoch time”?
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Early versions of unix measured system time in 1/60 s intervals. This meant that a 32-bit unsigned integer could only represent a span of time less than 829 days. For this reason, the time represented by the number 0 (called the epoch) had to be set in the very recent pas...
Efficient SQL test query or validation query that will work across all (or most) databases
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pandas: filter rows of DataFrame with operator chaining
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Loop backwards using indices in Python?
I am trying to loop from 100 to 0. How do I do this in Python?
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How to drop columns by name in a data frame
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vs2008编译boost详细步骤 - 开源 & Github - 清泛网 - 专注C/C++及内核技术
...不扣的“准”标准库。
Boost库中比较有名的几个库：
（1）Regex，正则表达式库；
（2）Spirit，LL parser framework，用C++代码直接表达EBNF；
（3）Graph，图组件和算法；
（4）Lambda，在调用的地方定义短小匿名的函数对象，很实用...
Get the latest record from mongodb collection
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This is a rehash of the previous answer but it's more likely to work on different mongodb vers...
MongoDB副本集详解 优于以往的主从模式 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...为mongodb-linux-x86_64-2.6.0
由三台虚拟机搭建，配置为单核,1G内存。实验环境如下:
MongoDB的副本集不同于以往的主从模式。
在集群Master故障的时候，副本集可以自动投票，选举出新的Master，并引导其余的Slave服务器连接新的Master...
Best Practice: Software Versioning [closed]
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