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What is the best way to ensure only one instance of a Bash script is running? [duplicate]
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If the script is the same across all users, you can use a lockfile approach. If you acquire the lock, proceed else show a message and exit.
As an example:
[Terminal #1] $ lockfile -r 0 /tmp/the.lock
[Terminal #1] $
[Terminal #2] $ lockfile -r 0 /tmp/the....
What are the “standard unambiguous date” formats for string-to-date conversion in R?
...te (+1). However, the error message "standard unambiguous format" is ironically ambiguous, to which the 23 previous questions attest. A more direct error message like, "format not recognized, see documentation" might improve user experience. Also, I don't believe "01/01/2000" is ISO-8601 ("2000-01-0...
Why is it slower to iterate over a small string than a small list?
...nd with timeit and noticed that doing a simple list comprehension over a small string took longer than doing the same operation on a list of small single character strings. Any explanation? It's almost 1.35 times as much time.
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Python - When to use file vs open
What's the difference between file and open in Python? When should I use which one? (Say I'm in 2.5)
6 Answers
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RuntimeError on windows trying python multiprocessing
...void creating subprocesses recursively.
Modified testMain.py:
import parallelTestModule
if __name__ == '__main__':
extractor = parallelTestModule.ParallelExtractor()
extractor.runInParallel(numProcesses=2, numThreads=4)
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How does Bluebird's util.toFastProperties function make an object's properties “fast”?
... eval("o" + o); // ensure no dead code elimination
}
Sans one or two small optimizations - all the below is still valid.
Let's first discuss what it does and why that's faster and then why it works.
What it does
The V8 engine uses two object representations:
Dictionary mode - in which object ar...
Python Infinity - Any caveats?
...involving inf:
>>> 0 * float("inf")
nan
Note that you will normally not get an inf value through usual arithmetic calculations:
>>> 2.0**2
4.0
>>> _**2
16.0
>>> _**2
256.0
>>> _**2
65536.0
>>> _**2
4294967296.0
>>> _**2
1.84467440737...
Realistic usage of the C99 'restrict' keyword?
...aw it mentioned. I read a brief description, stating that it would be basically a promise from the programmer that the pointer won't be used to point somewhere else.
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sed one-liner to convert all uppercase to lowercase?
I have a textfile in which some words are printed in ALL CAPS. I want to be able to just convert everything in the textfile to lowercase, using sed . That means that the first sentence would then read, 'i have a textfile in which some words are printed in all caps.'
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What are all the escape characters?
I know some of the escape characters in Java, e.g.
4 Answers
4
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