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What's a concise way to check that environment variables are set in a Unix shell script?
..."}
: ${DEST:?"Need to set DEST non-empty"}
Or, better (see section on 'Position of double quotes' below):
: "${STATE?Need to set STATE}"
: "${DEST:?Need to set DEST non-empty}"
The first variant (using just ?) requires STATE to be set, but STATE="" (an empty string) is OK — not exactly what you ...
Can an html element have multiple ids?
I understand that an id must be unique within an HTML/XHTML page.
18 Answers
18
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Compiling a java program into an executable [duplicate]
I've just made a simple program with Eclipse and I want to compile it into an executable, but simply can't seem to find out how to do it.
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Why is jquery's .ajax() method not sending my session cookie?
After logging in via $.ajax() to a site, I am trying to send a second $.ajax() request to that site - but when I check the headers sent using FireBug, there is no session cookie being included in the request.
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How do you check if a certain index exists in a table?
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You can do it using a straight forward select like this:
SELECT *
FROM sys.indexes
WHERE name='YourIndexName' AND object_id = OBJECT_ID('Schema.YourTableName')
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Why is Android Studio reporting “URI is not registered”? [closed]
...really like Resharper and noticed that the IDE had some of their functionality built into it. Having now created a default new project, I added a new layout file and wanted to change the existing default 'hello world' example layout, and I got an "URI is not registered" error on the following lines:...
Simpler way to create dictionary of separate variables?
... as a string but I don't know if Python has that much introspection capabilities. Something like:
27 Answers
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Null check in an enhanced for loop
...st won't fail.
If you get this list from somewhere else and don't know if it is ok or not you could create a utility method and use it like this:
for( Object o : safe( list ) ) {
// do whatever
}
And of course safe would be:
public static List safe( List other ) {
return other == null ...
Convert any object to a byte[]
I am writing a prototype TCP connection and I am having some trouble homogenizing the data to be sent.
13 Answers
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How can I safely create a nested directory?
... is the most elegant way to check if the directory a file is going to be written to exists, and if not, create the directory using Python? Here is what I tried:
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