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Test if characters are in a string
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edited Apr 14 at 17:04
TMS
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Linux: copy and create destination dir if it does not exist
...nd (or probably an option to cp) that creates the destination directory if it does not exist.
21 Answers
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Does return stop a loop?
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Yes, return stops execution and exits the function. return always** exits its function immediately, with no further execution if it's inside a for loop.
It is easily verified for yourself:
function returnMe() {
for (var i = 0; i < 2; i++) {
if (i...
Is it secure to store passwords as environment variables (rather than as plain text) in config files
I work on a few apps in rails, django (and a little bit of php), and one of the things that I started doing in some of them is storing database and other passwords as environment variables rather than plain text in certain config files (or in settings.py, for django apps).
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ALTER TABLE without locking the table?
...ySQL, the whole table is read-locked (allowing concurrent reads, but prohibiting concurrent writes) for the duration of the statement. If it's a big table, INSERT or UPDATE statements could be blocked for a looooong time. Is there a way to do a "hot alter", like adding a column in such a way that th...
How to check for valid email address? [duplicate]
Is there a good way to check a form input using regex to make sure it is a proper style email address? Been searching since last night and everybody that has answered peoples questions regarding this topic also seems to have problems with it if it is a subdomained email address.
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When and how should I use a ThreadLocal variable?
... object (I'm looking at you, SimpleDateFormat). Instead, give each thread its own instance of the object.
For example:
public class Foo
{
// SimpleDateFormat is not thread-safe, so give one to each thread
private static final ThreadLocal<SimpleDateFormat> formatter = new ThreadLocal...
Avoid synchronized(this) in Java?
... an
"accidentally" variant)
I'm more worried about accidentally. What it amounts to is that this use of this is part of your class' exposed interface, and should be documented. Sometimes the ability of other code to use your lock is desired. This is true of things like Collections.synchronize...
SQL JOIN - WHERE clause vs. ON clause
After reading it, this is not a duplicate of Explicit vs Implicit SQL Joins .
The answer may be related (or even the same) but the question is different.
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Can two applications listen to the same port?
...lications on the same machine bind to the same port and IP address? Taking it a step further, can one app listen to requests coming from a certain IP and the other to another remote IP?
I know I can have one application that starts off two threads (or forks) to have similar behavior, but can two ap...