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How to check if a symlink exists
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-L returns true if the "file" exists and is a symbolic link (the linked file may or may not exist). You want -f (returns true if file exists and is a regular file) or maybe just -e (returns true if file exists regardless of type).
According to the GNU manpage, ...
How to enable MySQL Query Log?
...he MySQL function that logs each SQL query statement received from clients and the time that query statement has submitted?
Can I do that in phpmyadmin or NaviCat?
How do I analyse the log?
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Declaration/definition of variables locations in ObjectiveC?
Ever since starting to work on iOS apps and objective C I've been really puzzled by the different locations where one could be declaring and defining variables. On one hand we have the traditional C approach, on the other we have the new ObjectiveC directives that add OO on top of that. Could you fo...
Check string for palindrome
... ++i1;
--i2;
}
return true;
}
Example:
Input is "andna".
i1 will be 0 and i2 will be 4.
First loop iteration we will compare word[0] and word[4]. They're equal, so we increment i1 (it's now 1) and decrement i2 (it's now 3).
So we then compare the n's. They're equal, so w...
What is non-blocking or asynchronous I/O in Node.js?
...rage is a blocking operation as it stalls execution to read. On the other hand, fetch is a non-blocking operation as it does not stall alert(3) from execution.
// Blocking: 1,... 2
alert(1);
var value = localStorage.getItem('foo');
alert(2);
// Non-blocking: 1, 3,... 2
alert(1);
fetch('example.com...
What is the fastest substring search algorithm?
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Build up a test library of likely needles and haystacks. Profile the tests on several search algorithms, including brute force. Pick the one that performs best with your data.
Boyer-Moore uses a bad character table with a good suffix table.
Boyer-Moore-Horspool u...
Check if a string matches a regex in Bash script
...=~ ^regex$ ]] && echo "matched" || echo "did not match"
where commands after && are executed if the test is successful, and commands after || are executed if the test is unsuccessful.
Note this is based on the solution by Aleks-Daniel Jakimenko in User input date format verification...
what's the difference between “hadoop fs” shell commands and “hdfs dfs” shell commands?
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Following are the three commands which appears same but have minute differences
hadoop fs {args}
hadoop dfs {args}
hdfs dfs {args}
hadoop fs <args>
FS relates to a generic file system which can point to any file systems like local, HDF...
Can I assume (bool)true == (int)1 for any C++ compiler?
...are redundant. In your expression:
true == 1
Integral promotion applies and the bool value will be promoted to an int and this promotion must yield 1.
Reference: 4.7 [conv.integral] / 4: If the source type is bool... true is converted to one.
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Why are there two kinds of functions in Elixir?
I'm learning Elixir and wonder why it has two types of function definitions:
8 Answers
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