MySQL: @variable vs. variable. What's the difference?
In MySQL, @variable indicates a user-defined variable. You can define your own. SET @a = 'test'; SELECT @a; Outside of stored programs, a variable, without @, is a system variable, …
What are the special dollar sign shell variables? - Stack Overflow
Sep 14, 2012 · $! is the PID of the most recent background command. $0 is the name of the shell or shell script. Most of the above can be found under Special Parameters in the Bash …
Setting Windows PowerShell environment variables - Stack Overflow
I have found out that setting the PATH environment variable affects only the old command prompt. PowerShell seems to have different environment settings. How do I change the …
How do you test if a variable is undefined? - Stack Overflow
Oct 23, 2025 · How do you test if a variable is undefined? Asked 15 years, 1 month ago Modified 10 days ago Viewed 431k times
Why would a JavaScript variable start with a dollar sign?
The questions wasn't 'Can a JavasScript variable start with a $?', but 'Why would a ...' . thee OP was looking for a reason to use such a naming convention. Protected question. To answer this …
How to declare a variable in a template in Angular
@matttm #t is a template variable that stores the ng-template. It is used in [ngTemplateOutlet]="t" to make the ng-template reference itself.
What is the Python equivalent of static variables inside a function ...
Nov 11, 2008 · Instead of creating a function having a static local variable, you can always create what is called a "function object" and give it a standard (non-static) member variable.
python - How do I create variable variables? - Stack Overflow
I know that some other languages, such as PHP, support a concept of "variable variable names" - that is, the contents of a string can be used as part of a variable name. I heard …
Setting JAVA_HOME environment variable in MS Windows
12 Set the JAVA_HOME Variable Windows 7 – Right click My Computer and select Properties > Advanced Windows 8 – Go to Control Panel > System > Advanced System Settings Windows …
How to pass a variable into a YAML template parameter and use it …
Feb 15, 2025 · If you are passing a variable into a template parameter with the intention of using it as part of another runtime expression, the easiest method is to copy the parameter to a variable.