How do I detect whether sys.stdout is attached to terminal or not?

In Python, you can determine whether sys.stdout is connected to a terminal by using the sys.stdout.isatty() method. This method returns a boolean value: it returns True if sys.stdout is connected to a terminal, and False otherwise.

For example, if you want to check in your script whether the output is redirected to a file or another non-terminal device, you can do the following:

python
import sys

if sys.stdout.isatty():
    print("Connected to a terminal")
else:
    print("Not connected to a terminal")

This code first imports the sys module and then uses isatty() to check sys.stdout. Based on the return value, it prints the appropriate message.

This feature is particularly useful for handling output formatting or differences in behavior between interactive and non-interactive environments. For instance, if the output is directly sent to the terminal, you might add colors or special formatting to improve readability; however, if the output is redirected to a file, these additional formats could cause parsing issues.