How to check what variables exist in current python environment/workspace
84783
Enumerate or list all variables in a program of [your favorite language here]
83782
How to check a not-defined variable in JavaScript
146844
How do I *reliably* and *simply* get the current shell interpreter name?
59066
`if __name__ == '__main__'` equivalent in Ruby
53507
Test if executable exists in Python?
132919
Checking via ArcPy if ArcMap is in edit session?
31627
How to print only defined variables (shell and/or environment variables) in bash
95193
Find out current working directory of a running process?
6820
Where to declare environment variables?
114278
Environment Variables for Windows' Built-in Libraries?
19329
How to check if directory exists in %PATH%?
53586
How can I type-check variables in Python?
88821
How do I get and set Environment variables in C#?
122936
Indirectly access environment variable
105531
Determining if a variable is within range?
3528
How to check if a variable is the same as at least one of two other variables?
154469
How can I access directory-local variables in my major mode hooks?