Why do people write the #!/usr/bin/env python shebang on the first line of a Python script?

Question

It seems to me like the files run the same without that line.

Answer 1

• If you have installed many versions of Python, then #!/usr/bin/env ensures that the interpreter will use the first installed version on your environment's $PATH. 

• If you are using Unix, an executable file that is meant to be interpreted can indicate what interpreter to use by having a #! at the start of the first line, followed by the interpreter (and any flags it may need).

• For any other operating systems, of course, this rule does not apply (but that "shebang line" does no harm, and will help if you ever copy that script to a platform with a Unix base, such as Linux, Mac, etc).

 

Comments

Where should I write it? (I am a beginner)