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What is the difference between save and export in Docker?
I am playing around with Docker for a couple of days and I already made some images (which was really fun!). Now I want to persist my work and came to the save and export commands, but I don't fully understand them.
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Hidden features of mod_rewrite
...of it work. As a result I've compiled a few notes on common functionality, and perhaps a few annoying nuances.
8 Answers
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Standard alternative to GCC's ##__VA_ARGS__ trick?
...preprocessor features; you must use some extension to the language. clang and icc have adopted this GCC extension, but MSVC has not.
Back in 2001 I wrote up the GCC extension for standardization (and the related extension that lets you use a name other than __VA_ARGS__ for the rest-parameter) in ...
How to check if an object is a list or tuple (but not string)?
...es I stumbled upon bugs where a function passes a str object by mistake, and the target function does for x in lst assuming that lst is actually a list or tuple .
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Using StringWriter for XML Serialization
...t prefixed with an upper-case "N", hence an 8-bit encoding, such as UTF-8) and not an NVARCHAR string (prefixed with an upper-case "N", hence the 16-bit UTF-16 LE encoding).
The fix should have been as simple as:
In the first case, when adding the declaration stating encoding="utf-8": simply don'...
C Macro definition to determine big endian or little endian machine?
... edited Mar 29 '18 at 22:02
Alexander Stohr
1171010 bronze badges
answered Jan 20 '10 at 16:39
ChristophChrist...
Good reasons NOT to use a relational database?
Can you please point to alternative data storage tools and give good reasons to use them instead of good-old relational databases? In my opinion, most applications rarely use the full power of SQL--it would be interesting to see how to build an SQL-free application.
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Rails create or update magic?
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Rails 6
Rails 6 added an upsert and upsert_all methods that deliver this functionality.
Model.upsert(column_name: value)
[upsert] It does not instantiate any models nor does it trigger Active Record callbacks or validations.
Rails 5, 4, and 3
Not ...
Comparing numbers in Bash
...hen
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fi
For POSIX shells that don't support (()), you can use -lt and -gt.
if [ "$a" -gt "$b" ]; then
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fi
You can get a full list of comparison operators with help test or man test.
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Cycles in family tree software
I am the developer of some family tree software (written in C++ and Qt). I had no problems until one of my customers mailed me a bug report. The problem is that the customer has two children with their own daughter, and, as a result, he can't use my software because of errors.
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