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Why is whitespace sometimes needed around metacharacters?
...s a list of characters that separate tokens in BASH. These characters are called metacharacters and they are |, &, ;, (, ), <, >, space and tab. On the other hand, curly braces ({ and }) are just ordinary characters that make up words.
Omitting the second space before } will do, since &am...
How can I start PostgreSQL server on Mac OS X?
...
The Homebrew package manager includes launchctl plists to start automatically. For more information, run brew info postgres.
Start manually
pg_ctl -D /usr/local/var/postgres start
Stop manually
pg_ctl -D /usr/local/var/postgres stop
Start automatically
"To have launchd start postgresql now and res...
How do I check for C++11 support?
...t have (partial) compiler-level support versus a standard C++ library with all the C++11 changes.
So Boost's defines mentioned in another answer remain the only sane way to figure out if there is, for example, support for C++11 threads and other specific parts of the standard.
...
Unable to find specific subclass of NSManagedObject
...://stackoverflow.com/a/31287260/1187415).
Remark: This answer was originally written for Xcode 6.
There were some changes in the various Xcode 7 beta releases with
respect to this problem. Since it is an accepted answer with many
upvotes and links to it, I have tried to summarize the situation
fo...
What is the “Execute Around” idiom?
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Basically it's the pattern where you write a method to do things which are always required, e.g. resource allocation and clean-up, and make the caller pass in "what we want to do with the resource". For example:
public interface ...
MySQL SELECT only not null values
...hough...
SELECT val1 AS val
FROM your_table
WHERE val1 IS NOT NULL
UNION ALL
SELECT val2
FROM your_table
WHERE val2 IS NOT NULL
/*And so on for all your columns*/
The disadvantage of the above is that it scans the table multiple times once for each column. That may possibly be avoided by the b...
Regex for password must contain at least eight characters, at least one number and both lower and up
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"^(?=.*[A-Za-z])(?=.*\d)[A-Za-z\d]{8,}$" does not allow symbols as one of the 8 characters
– Wee
Jan 6 '15 at 2:30
2
...
How do I ignore files in a directory in Git?
...
This is actually a copy-paste from the git documentation
– mcont
Aug 17 '18 at 10:00
1
...
What is a simple command line program or script to backup SQL server databases?
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There's a good script to backup all user databases in one go here: mssqltips.com/tip.asp?tip=1070
– Marnix van Valen
Sep 22 '09 at 14:47
...
How can I convert ereg expressions to preg in PHP?
...pha-numeric, a backslash or a whitespace character. The most used are generally ~, / and #.
You can also use matching brackets:
preg_match('[^hello]', $str);
preg_match('(^hello)', $str);
preg_match('{^hello}', $str);
// etc
If your delimiter is found in the regular expression, you have to escap...