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How can I declare and use Boolean variables in a shell script?
......
if [ "$the_world_is_flat" = true ] ; then
echo 'Be careful not to fall off!'
fi
Original Answer
Caveats: https://stackoverflow.com/a/21210966/89391
the_world_is_flat=true
# ...do something interesting...
if $the_world_is_flat ; then
echo 'Be careful not to fall off!'
fi
From: Usi...
What is the difference between Class.getResource() and ClassLoader.getResource()?
...esource paths are always deemed to be absolute.
So the following are basically equivalent:
foo.bar.Baz.class.getResource("xyz.txt");
foo.bar.Baz.class.getClassLoader().getResource("foo/bar/xyz.txt");
And so are these (but they're different from the above):
foo.bar.Baz.class.getResource("/data/x...
What is the use case of noop [:] in bash?
... to do.
while keep_waiting; do
: # busy-wait
done
The : builtin dates all the way back to the Thompson shell, it was present in Unix v6. : was a label indicator for the Thompson shell's goto statement. The label could be any text, so : doubled up as a comment indicator (if there is no goto comm...
How to quickly clear a JavaScript Object?
...object).
In this example, I believe setting the length to 0 still leaves all of the elements for garbage collection.
You could add this to Object.prototype if it's something you'd frequently use. Yes it's linear in complexity, but anything that doesn't do garbage collection later will be.
This is ...
Assigning default values to shell variables with a single command in bash
...
Very close to what you posted, actually:
FOO=${VARIABLE:-default} # If variable not set or null, use default.
Or, which will assign default to VARIABLE as well:
FOO=${VARIABLE:=default} # If variable not set or null, set it to default.
...
When should you use a class vs a struct in C++?
...
A struct with no modifiers or methods is called a POD struct, which exists as a backwards compatible interface with C libraries as it is (supposedly) guaranteed to be laid out as though it were a C struct. Apart from this one exception though, the only difference is ...
PostgreSQL - how to quickly drop a user with existing privileges
... experimenting. Is there any way to drop the user without having to revoke all his rights manually first, or revoke all the grants a user has?
...
Return a `struct` from a function in C
... from a function, to which I replied: "No! You'd return pointers to dynamically malloc ed struct s instead."
9 Answers
...
When vectors are allocated, do they use memory on the heap or the stack?
Are all of the following statements true?
5 Answers
5
...
Django REST Framework: adding additional field to ModelSerializer
...
I think SerializerMethodField is what you're looking for:
class FooSerializer(serializers.ModelSerializer):
my_field = serializers.SerializerMethodField('is_named_bar')
def is_named_bar(self, foo):
return foo.name == "bar"
class Meta:
model = Foo
fields = ('id', 'na...