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Check existence of input argument in a Bash shell script
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It is:
if [ $# -eq 0 ]
then
echo "No arguments supplied"
fi
The $# variable will tell you the number of input arguments the script was passed.
Or you can check if an argument is an empty string or not like:
if [ -z "$1...
Is there an equivalent of 'which' on the Windows command line?
...to find the full path to a program on the Windows command line, given just its name.
26 Answers
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Does it make any sense to use inline keyword with templates?
Since templates are defined within headers and compiler is able to determine if inlining a function is advantageous, does it make any sense? I've heard that modern compilers know better when to inline a function and are ignoring inline hint.
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How do I reflect over the members of dynamic object?
...o get a dictionary of properties and their values from an object declared with the dynamic keyword in .NET 4? It seems using reflection for this will not work.
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Moving and vanishing lines of code; trouble with Eclipse's XML Editor
Sometimes my code moves on its own or just disappears in the Eclipse XML editor.
7 Answers
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When and why to 'return false' in JavaScript?
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Often, in event handlers, such as onsubmit, returning false is a way to tell the event to not actually fire. So, say, in the onsubmit case, this would mean that the form is not submitted.
s...
Why does the C preprocessor interpret the word “linux” as the constant “1”?
...unix and vax was a way to allow code to detect at compile time what system it was being compiled for. There was no official language standard back then (beyond the reference material at the back of the first edition of K&R), and C code of any complexity was typically a complex maze of #ifdefs to...
Virtual/pure virtual explained
What exactly does it mean if a function is defined as virtual and is that the same as pure virtual?
12 Answers
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Converting from a string to boolean in Python?
... do convert from a string to a boolean in Python? I found this link . But it doesn't look like a proper way to do it. I.e. using built-in functionality, etc.
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How do I test for an empty JavaScript object?
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// because Object.keys(new Date()).length === 0;
// we have to do some additional check
Object.keys(obj).length === 0 && obj.constructor === Object
Note, though, that this creates an unnecessary array (the return value of keys).
Pre-ECMA 5:
function isEmpty(obj) {
for(var prop in obj)...