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How to tell if a string is not defined in a Bash shell script
... not set, you can use:
if [ -z "${VAR+xxx}" ]; then echo VAR is not set at all; fi
if [ -z "$VAR" ] && [ "${VAR+xxx}" = "xxx" ]; then echo VAR is set but empty; fi
You probably can combine the two tests on the second line into one with:
if [ -z "$VAR" -a "${VAR+xxx}" = "xxx" ]; then echo VA...
What exactly is a reentrant function?
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1. How is safely defined?
Semantically. In this case, this is not a hard-defined term. It just mean "You can do that, without risk".
2. If a program can be safely executed concurrently, does it always mean that it is reentrant?
No.
For example, let's have ...
Do I need all three constructors for an Android custom view?
...s/MyCustomStyle"
...
/>
the 2nd constructor will also be called and default the style to MyCustomStyle before applying explicit XML attributes.
The third constructor is usually used when you want all of the Views in your application to have the same style.
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@AspectJ pointcut for all methods of a class with specific annotation
I want to monitor all public methods of all Classes with specified annotation (say @Monitor) (note: Annotation is at class level). What could be a possible pointcut for this?
Note: I am using @AspectJ style Spring AOP.
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Handlebars.js Else If
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{{#if FriendStatus.IsFriend}}
<div class="ui-state-default ui-corner-all" title=".ui-icon-mail-closed"><span class="ui-icon ui-icon-mail-closed"></span></div>
{{else if FriendStatus.FriendRequested}}
<div class="ui-state-default ui-corner-all" title=".ui-icon-check"&g...
Extracting an attribute value with beautifulsoup
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.find_all() returns list of all found elements, so:
input_tag = soup.find_all(attrs={"name" : "stainfo"})
input_tag is a list (probably containing only one element). Depending on what you want exactly you either should do:
out...
How to enable mod_rewrite for Apache 2.2
I've got fresh install of Apache 2.2 on my Vista machine, everything works fine, except mod rewrite.
15 Answers
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Pretty git branch graphs
I've seen some books and articles have some really pretty looking graphs of git branches and commits. How can I make high-quality printable images of git history?
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What are enums and why are they useful?
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You should always use enums when a variable (especially a method parameter) can only take one out of a small set of possible values. Examples would be things like type constants (contract status: "permanent", "temp", "apprentice"), or flags ("execute now", "defer execution")....
Guid is all 0's (zeros)?
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Use the static method Guid.NewGuid() instead of calling the default constructor.
var responseObject = proxy.CallService(new RequestObject
{
Data = "misc. data",
Guid = Guid.NewGuid()
});
s...