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Check if a string matches a regex in Bash script
... can define a regex in Bash matching the format you want. This way you can do:
[[ $date =~ ^regex$ ]] && 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 i...
Run a callback only if an attribute has changed in Rails
...
Rails 5.1+
class Page < ActiveRecord::Base
before_save :do_something, if: :will_save_change_to_status_id?
private
def do_something
# ...
end
end
The commit that changed ActiveRecord::Dirty is here: https://github.com/rails/rails/commit/16ae3db5a5c6a08383b974ae6c96faa...
Disadvantages of Test Driven Development? [closed]
What do I lose by adopting test driven design?
31 Answers
31
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How do I escape the wildcard/asterisk character in bash?
...haviour. So use echo "$foo" in instead of just echo $foo.
LONG ANSWER
I do think this example warrants further explanation because there is more going on than it might seem on the face of it.
I can see where your confusion comes in because after you ran your first example you probably thought to...
How do I horizontally center a span element inside a div
... project' inside the surrounding div. Can someone point out what I need to do to make this work?
7 Answers
...
What is an undefined reference/unresolved external symbol error and how do I fix it?
... linking, it simply assumes that that symbol was defined somewhere, but it doesn't yet care where. The linking phase is responsible for finding the symbol and correctly linking it to b.cpp (well, actually to the object or library that uses it).
If you're using Microsoft Visual Studio, you'll see tha...
How do I strip non alphanumeric characters from a string and keep spaces?
...ion: @search_query.gsub(/[^0-9a-z\\s]/i, '')
– David Douglas
Dec 6 '13 at 12:09
6
slightly less w...
Defeating a Poker Bot
...y, there is
a tiny tiny chance this is a real
human. (However some players do have the ability to play very large hand volumes which to the inexperienced eye would appear to be a bot)
Throw it glitches. If you suspect a
player is a bot, change all their
playing card positions off a few
pixels on th...
Optimal settings for exporting SVGs for the web from Illustrator?
...upport SVG Tiny and not the full spec, so go for SVG 1.1.
Note: SVG Tiny does not reduce the file size, it's just a subset of SVG that is adequate for low processing power devices. It will discard gradients, opacity, embedded fonts and filters. Erik Dahlström says: All SVG 1.1 full viewers should...
Why would an Enum implement an Interface?
...
Enums don't just have to represent passive sets (e.g. colours). They can represent more complex objects with functionality, and so you're then likely to want to add further functionality to these - e.g. you may have interfaces such...