shell - Setting environment variable in /usr/bin/env hangs process on Linux -

while man env on linux seems indicate can set new environment variables before executing command. unfortunately, when set new variables in file's shebang on linux systems, file never executes.

#!/usr/bin/env var1=foo bash echo $var1 

when execute file on centos or ubuntu machine, sits there.

$ ./shell-env.sh <nothing happens> 

what find particularly bizarre works fine on os x bsd env.

$ ./shell-env.sh foo $ 

is difference between bsd env , linux env? why man pages linux seem should work same way on bsd?

p.s. use case here override path variable, can try find ruby on system that's not on path.

thank in advance!

there's way manipulate environment before executing ruby script, without using wrapper script of kind, it's not pretty:

#!/bin/bash export foo=bar exec ruby -x "$0" "$@"  #!ruby puts env['foo'] 

this reserved esoteric situations need manipulate e.g. path or ld_library_path before executing program, , needs self-contained reason. works perl , possibly others too!