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How to store a command in a variable in a shell script?
... that variable can be set by someone with less privileges. (Iterating over all subdirectories in /tmp, for instance? You'd better trust every single user on the system to not make one called $'/tmp/evil-$(rm -rf $HOME)\'$(rm -rf $HOME)\'/').
– Charles Duffy
Jun...
How to report an error from a SQL Server user-defined function
... wotta hack" :) I welcome any better solution for this case!
create table foo (
ID nvarchar(255),
Data nvarchar(255)
)
go
insert into foo (ID, Data) values ('Green Eggs', 'Ham')
go
create function dbo.GetFoo(@aID nvarchar(255)) returns table as return (
select *, 0 as CausesError from...
Better to 'try' something and catch the exception or test if it's possible first to avoid an excepti
...est option when the index is probably in the list and the IndexError is usually not raised. This way you avoid the need for an extra lookup by if index < len(my_list).
Python encourages the use of exceptions, which you handle is a phrase from Dive Into Python. Your example not only handles the e...
How does the “this” keyword work?
...ains in JavaScript.
Once you start getting used to this, the rules are actually pretty simple. The ECMAScript 5.1 Standard defines this:
§11.1.1 The this keyword
The this keyword evaluates to the value of the ThisBinding of the current execution context
ThisBinding is something that the JavaScrip...
Recursive Lock (Mutex) vs Non-Recursive Lock (Mutex)
POSIX allows mutexes to be recursive. That means the same thread can lock the same mutex twice and won't deadlock. Of course it also needs to unlock it twice, otherwise no other thread can obtain the mutex. Not all systems supporting pthreads also support recursive mutexes, but if they want to be P...
Is there a performance gain in using single quotes vs double quotes in ruby?
...t waste your time.
Actual interpolation is a different story, of course. 'foo' will be almost exactly 1 second faster than "#{sleep 1; nil}foo".
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How to add reference to a method parameter in javadoc?
...ding the docs for javadoc there is no such feature.
Don't use <code>foo</code> as recommended in other answers; you can use {@code foo}. This is especially good to know when you refer to a generic type such as {@code Iterator<String>} -- sure looks nicer than <code>Iterator...
sed: print only matching group
...uses the entire line to be replaced with the contents of the group
echo "foo bar <foo> bla 1 2 3.4" |
sed -n 's/.*\([0-9][0-9]*[\ \t][0-9.]*[ \t]*$\)/\1/p'
2 3.4
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Object-orientation in C
... describes it.
Exception in C is a C89 implementation of the TRY-CATCH-FINALLY found in other OO languages. It comes with a testsuite and some examples.
Both by Laurent Deniau, which is working a lot on OOP in C.
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How do I get the parent directory in Python?
...that does nothing but string manipulation. To verify if the pathname actually exist requires a disk access. Depends on the application this may or may not be desirable.
– Wai Yip Tung
May 18 '10 at 19:45
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