Preferred way of #! in shell scripts

Question

I searched google but couldn't find an answer to this rather simple question. I have a python script that has the hash-bang (#!) on the first line:

#!/usr/bin/python

However, what if this is run on a computer with python in /bin/python or /usr/local/bin/python, or some other place? There has to be a better way to set the interpreter for a shell script. It should be possible to set it via $PATH, as that will know where to find python if it's installed on the system.

Answer 1

Use env.

#!/usr/bin/env python

It's not bulletproof, but it covers more cases than /usr/bin/python.

Answer 2

Use

#!/usr/bin/env python

env is virtually always in /usr/bin, and will execute any program in the PATH.

Answer 3

Some people prefer to start with:

#!/usr/bin/env python

Not sure that this is a vast improvement as you're now assuming that python is in the path and that it's the right version, but it's an option.