How do I set an environment variable in the shebang (#!) of a script that will be run by Bash?

Question

Or, why doesn't this work, assuming you correctly set the file as executable? (On my system it just hangs, but can be killed with ^C.)

#!/usr/bin/env TEST=TEST python
print('hello')

While this does:

#!/usr/bin/env python
print('hello')

As does this:

[fred@pc build]$ /usr/bin/env TEST=TEST python hello.py 
hello

Answer 1

Since version 8.30 env has the option -S, which make things work also in linux:

Use

#!/usr/bin/env -S TEST=TEST python