Nope, there are systems in which it's in /bin/env, though you have to go fairly exotic before you find one that doesn't at least have a symlink in /usr/bin. I d

Nope, there are systems in which it's in /bin/env, though you have to go fairly exotic before you find one that doesn't at least have a symlink in /usr/bin. I don't believe POSIX says anything about it http://www.in-ulm.de/~mascheck/various/shebang/#env http://www.in-ulm.de/~mascheck/various/shebang/#env In fact, POSIX doesn't even standardize the shebang at all; it is simply mentioned as a possible extension.