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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...
When should I use a NoSQL database instead of a relational database? Is it okay to use both on the s
...proven and suitable for 99% of the real world applications. You can practically do anything with relational databases.
But, there are limitations on speed and scaling when it comes to massive high availability data stores. For example, Google and Amazon have terabytes of data stored in big data cen...
How to make IPython notebook matplotlib plot inline
...rt numpy as np
import matplotlib.pyplot as plt
You can also always start all your IPython kernels in inline mode by default by setting the following config options in your config files:
c.IPKernelApp.matplotlib=<CaselessStrEnum>
Default: None
Choices: ['auto', 'gtk', 'gtk3', 'inline', '...
Remove all elements contained in another array
I am looking for an efficient way to remove all elements from a javascript array if they are present in another array.
14 A...
Something like 'contains any' for Java set?
...
Actually it will short-circuit as soon as it finds the first common element
– Xipo
Dec 15 '16 at 10:54
3
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How to list the files inside a JAR file?
I have this code which reads all the files from a directory.
16 Answers
16
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Getting Chrome to accept self-signed localhost certificate
...tificate for the localhost CN. Firefox accepts this certificate after initially complaining about it, as expected. Chrome and IE, however, refuse to accept it, even after adding the certificate to the system certificate store under Trusted Roots. Even though the certificate is listed as correctly in...
Replace multiple whitespaces with single whitespace in JavaScript string
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Augmenting prototype of the standard object is a really controversial pattern. I wouldn't recommend it for such a basic question.
– bjornd
Nov 2 '12 at 9:06
...
Meaning of “[: too many arguments” error from if [] (square brackets)
...
# if [ hello world == 0 ]
fi
The same will be true for any function call that puts down a string containing spaces or other special characters.
Easy fix
Wrap the variable output in double quotes, forcing it to stay as one string (therefore one argument). For example,
VARIABLE=$(/some/comm...
Using socket.io in Express 4 and express-generator's /bin/www
...
A little different approach to initiate socket.io, it groups all related code in one place:
bin/www
/**
* Socket.io
*/
var socketApi = require('../socketApi');
var io = socketApi.io;
io.attach(server);
socketApi.js
var socket_io = require('socket.io');
var io = socket_io();
var ...