Check if a program exists from a python script
53507
Test if executable exists in Python?
35441
How to tell if a string contains valid Python code
79883
Test for presence of specific object or managed package?
50579
How to find out if a file exists in C# / .NET?
92335
Check if a file is executable
41491
Make sure only a single instance of a program is running
84345
How can I tell if another instance of my program is already running?
157008
Check if counter exists
100609
How can I find and run an application that's already installed?
68272
Checking a Python module version at runtime
49250
Can the C preprocessor be used to tell if a file exists?
1949
How do I check whether a file exists without exceptions?
86265
Check for Process if Same is Running
8512
How to check if a process is running via a batch script
110829
The "proper" way to test if a service is running in a script
23208
How can I check if a file exists in Perl?
137660
Avoid running the script if a variable is not defined