PROMPT> which python
/usr/local/bin/python
PROMPT> ls -al
total 8
drwxr-xr-x 3 jon 102B Aug 27 20:15 ./
drwxrwxr-x 21 jon 714B Aug 27 20:15 ../
-rwxr-xr-x 1 jon 54B Aug 27 20:15 build*
PROMPT> cat build
#! /usr/local/bin/ python
print 'hello world - build'
PROMPT> ./build
-bash: ./build: /usr/local/bin/: bad interpreter: Permission denied
私は何を間違っていますか?