Can't run Python .py files from terminal on Mac

Question

I just downloaded Python 3.2 to Mac OS 10.6 environment. I'm new to programming and am trying to run my first stand-alone .py file, but I keep getting an error message saying "no such directory or file." The name of the file is "script1.py" and I saved it to /Users/billp/Documents. When I open the Terminal to run the file I type:

python script1.py

I've also tried adding this line to the beginning of the script:

#!/usr/local/bin/python

As well as this one:

#!/usr/bin/env python

Yet, I keep getting the same error message. Any help would be greatly appreciated.

Answer 1

Make sure you are in the right working directory after opening terminal. Type

cd /Users/billp/Documents/

(use tab to autocomplete)

then

python ./script1.py

This way you are launching python executable and passing it path to your file as the first argument. The shebang #! line you mentioned allows you to launch your script directly, like this: ./script1.py, but you need to mark the file as executable chmod +x script1.py and provide path to interpreter (python) after the shebang. #!/usr/bin/env python references your default python installation.

The ./ stands for current directory. By default when you type script1.py your shell (which is the thing that you type commands into, through the terminal) would look for executable file in special folders listed in PATH env variable. script1.py is not usually there, so you would see -bash: script1.py: command not found. python, on the other hand is on the PATH so it should work.