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What is the $? (dollar question mark) variable in shell scripting? [duplicate]
...is called by the exit() ANSI C function, and indirectly when you do return from main.
the process that called the exiting child process (Bash), often with fork + exec, can retrieve the exit status of the child with the wait system call
Consider the Bash code:
$ false
$ echo $?
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The C "equivalen...
What is a vertical tab?
...rm footer. Generally it was coded in the program as a character constant. From the keyboard, it would be CTRL-K.
I don't believe anyone would have a reason to use it any more. Most forms are generated in a printer control language like postscript.
@Talvi Wilson noted it used in python '\v'.
...
How to override the properties of a CSS class using another CSS class
...it breaks natural cascading in your style sheet.
Following diagram taken from css-tricks.com will help you produce right specificity for your element based on a points structure. Whichever specificity has higher points, will win. Sounds like a game - doesn't it?
Checkout sample calculations her...
How to find index of all occurrences of element in array?
...s an optional second parameter that specifies the index to start searching from, so you can call it in a loop to find all instances of a particular value:
function getAllIndexes(arr, val) {
var indexes = [], i = -1;
while ((i = arr.indexOf(val, i+1)) != -1){
indexes.push(i);
}
...
'transform3d' not working with position: fixed children
...uld be to avoid transforms for the time being if you're going to use fixed from inside of it.
– saml
Aug 26 '13 at 15:56
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UIViewController viewDidLoad vs. viewWillAppear: What is the proper division of labor?
...me you go to the "Now Playing" view.
However, when you are loading things from a server, you also have to think about latency. If you pack all of your network communication into viewDidLoad or viewWillAppear, they will be executed before the user gets to see the view - possibly resulting a short fr...
How to compare versions in Ruby?
...default; you need a require 'rubygems' to get access to the Gem namespace. From 1.9 on, however, it's automatically included.
– Mark Reed
Feb 12 '14 at 14:35
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Why is std::min failing when windows.h is included?
...here I can't simply use NOMINMAX as some part of the code use drawing code from Windows that needs the macros.
– Mickaël C. Guimarães
May 29 '15 at 19:59
1
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How do I ignore a directory with SVN?
... 'cache' dir still will be listed in 'svn st'. Is there a way to remove it from the view? (without delete from the disk)
– Tom Brito
Aug 1 '16 at 20:45
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if (key in object) or if(object.hasOwnProperty(key)
... returns true always, if property is accessible by the object, directly or from the prototype
hasOwnProperty() returns true only if property exists on the instance, but not on its prototype
If we want to check that some property exist on the prototype, logically, we would say:
console.log(('name'...